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Les diagrammes suivants illustrent la methode. 1 2 3 4 5 6 ::-?=ss'*r^«i?'isaK5tamP2r^!eiiKsair^ MICROCOfY RESOIUTION TBT CHART ANSI and ISO TEST CHART No 2! Ui I 2.8 m 2.2 1.8 1.6 ^ -APPL IED \M^!3E_ I r-.^ WofHesr#f. Ns» York '4609 -^Jk •■S^ -'''6)^82 CiOO r^^r.e **^. fe:^ ^1 ■ iwM ^^.l¥&.r. '^H^H KqPhSo'IH^B ■ i ..»i^ B r'^x \bk.k^ C'^^H^^^H '.."■i If'i"° l:.^3fln^B^ f-Tt-ir;-:. J*-ii^f^- • i 7 ■■■:Zli^ - I ' ■ .' ■ . i > |--. , . ■■■■"" 1 -'"■ - fefct ; :-.iJ=&...i- '^r' :aKa^:£ -. .. ourneY5 of Observation ByT.A. Rickard Editor of the Mining and Scientific Press; formerly Editor of the Enginekring and Mining Journal; Associate of the Royal School of Mines; Member of the Institution of Mining and Metallurgy; Member of the American Institute of Mining Engineers ; State Geologist of Colorado ( 1895-1901 ) ; Author of 'The Stamp-Milling of Gold Ores,' 'The Copper Mines of Lake Superior,' 'Ihe Sampling and Estimation of Ore in a Mine,' 'Pyrite Smelting," 'The Economics of Mining.' SAN FRANCISCO 1907 Copyriuhl IQOJ Bv :iii MfMiNS AND Sciimific P^uf Printed br San Franciico T)edictttioii TT^i y M'/t^ ^:^^^Uyi^ ^ r^if. t ' y 1 (» TJrefflce Thi' book records the observations made by a trave!«* A'ho happened to be a mining engineer; it is supp cd to belong to the typ« ' <" voyages meiallurgi' ques, such a? were published ir "efore the globe had been over-run by tourists s distant corners rendered commonplace by the -ggcrations of the daily press. To the members of my profession the comment concerning the industrial conditions, geo- logical structure, mining methods, and metallurgical practice of southwestern Colorado and a progressive part of Mexico m\\ have the interest that comes from observations which reflect a point of view somewhat similar to their own, while to the layman the not too severely technical descriptions, aided by beautiful photographs, will afford information of a kind rarely obtainable except in periodicals devoted to tech- nology. It is hoped that this record of conditions in two representative mining regions may have a his- torical value '■ the days to come. Moreover, I have thought it Wi o publish *his volume as an expres- sion of thank .o those who were kind enough to give me m :ny valuable data and to make my travels pleasa.H hy their courtesy and hospitality. I am inr ebtc \o many friends for the photographs, for only a ic v of them are my own. From the United States Geological Survey were obtained half a dozen of the best views of the San Juan; other acknowledg- ments appear in the text. „ ^ . , T. A. RICKARD. >an Francisco, Septembe. 15, 1907. 5lllnes of Mlexlco Being the record of a journey from New York to Mexico, together witJ a descrip- tion of the mining industry- . F] Oro, Pachuca, and Guanajuato, as observed in October, 1905. Reprinted by permission from the Mining and Scien rinc Press. t :t * *' ;, " '~^c •"■•»,»■ ■•'ixTi^' ISBSsr— ^sHT Contenb Chapter p^^^^ 1. New York from the Harbor. A Farewell to Man- hattan 2. Havr la. A Cigar Factory. The Spanish Conquest. Hernando Cortez. The First Sight of Orizaba . 5 3. Vera Cruz. On the Mexican Railway. Tropical Vegetation. Coffee Plantations. At Orizaba . 13 4. The Physiography of Mexico. Outlines of History. At Esperanza. The Maguey and Pulque. A National Habit. Arrival at the City of Mexico . 18 5. Geology Along the Railroad. Precious Metals in the Volcanic Dust. Vein Formation. The Sulphur of Popocatepetl ^e 6. The City of Mexico. First Impressions. The School of Mines. Memories of Del Rio. The Meteor- ites. Cortez 29 7. El Oro. Rich Mines. The Geology of the District. The Mexico Mine. The Structure of the Lodes. In the El Oro Mine. A Wide Lode-Channel. Faults .- 8. Geology of the Esperanza Mine. Interesting Struc- ture. A Big Fault. Rich Orebody. Story of the Discovery. Character of the Ore ... 43 9. Development of the Milling Practice at El Oro. Be- ginning of Cyanidation. First Big Mill. Change of Method. Tube-Mills and Re-Grinding . . 54 10. Treatment of Slime. Use of Lead Acetate. Addi- tion of Lime. Its Double Function. Settlement of the Slime. The Tube-Mills. Their Lining. Successful Work 5j tx CONTENTS Chapter Page 11. Further Notes on El Oro Practice. The Stamp-Mill. Mortars and Guides. Apparatus for Sizing. The Precipitation House. Filter-Presses. Record of Tests 69 12. The Mill of the Esperanza. Use of iluntington Mills. Treatment of Sand. No Amalgamation. Extrac- tion 76 13. Mining Methods in the El Oro Mine, riiamond- Drilling in the Esperanza. Timbering Bad Ground. Precautions Taken. Laying of 1'rack. Excellent System "9 14. Taxes. The Dynamite Imposition. Electric Power. Dos Estrellas. It? Discovery. The Humor of Cyaniding. How Boundary Marks Are Pre- served 93 15. ^line Labor. The Contract System. Native Improv- idence and Skill. Difference of Locality. Poor Hammermen, but Willing Workers. Hot Mines loi 16. Pachuca. An Old Mining Centre. Ancient Methods. The Discovery of the Patio Process. Revolu- tionary Days. The Invasion of the Moderns . . 109 17. Real Del Monte. Old Machinery. The Viscaina Lode. Its Early Romance. La Difficultad. An Electrical Pump. Lode Structure. Local Ge- ology. Scenery 117 18. The Reduction Works of Pachuca. The Hacienda de Guadalupe. Treatment on the Patiu. A Metal- lurgical Survival. Some Criticisms .... 129 19. The Chemistry of the Patio Process. Chemical Equations. Observations of Humboldt. Loss of Mercury. Contrast of Policy 139 X •'f-F^i'^-'^aa^.f^S" ^■■w.^'j:-ijfsmi:-^^iMRimkw^ CONTENTS f 1 i3 Chapter Page 20. Other Metallurgical Processes. The Hacienda la Union. Kroencke's Method. Tube-Mills. The Barrel Process. Francke's Process. Chilean Mills. Retorting the Am gam. The Planilia . 148 21. First Glimpse of Guanajuato. The History of Local Mining. The Veta Madre, and Its Bonanzas. Rich Mine-Owners. The Count of Valenciara. Story of the Church. Decadence of the Dis: ot 160 22. Guanajuato at Its Height. Deep Mining. Visit of Humboldt. Decadence. La Luz. The Revival. \ii American Invasion. The Story of Modern Progress 169 2.3. Visit to the Old Mines. A Cavalcade. The Bustos Plant. Mechanic?! Devices Against Manual Labor. The Mother Lode. San Miguel de Rayas 176 24. A Grand View. Reminders of a Former Time. Eng- lish Enterprise 184 25. The Great Shafts of the Veta Madre. The Rayas. The Cata. The Tiro General. What Bryan Said of It. How It Was Unwatered. A Wonderful Spectacle 188 26. The Malacate and Its Operation. The Avio System. Electric Power. A Curious Difficulty. How the Eagles Interrupt the Current. A Strike . . 196 2y. The Peregrina Mine. Old Spanish Workings. Shrines Underground. Acetylene Lamps. Sam- pling a Dump 201 28. The Dumps of Guanajuato. How to Sample. The Mexican Idea. Two True Stories. The Biter Bit 2. xi WGm^^Kmf:it2iS:'im^K^'3^f^m^m^B^ii^ CONTENTS Chapter 29. 30. Page The Geology of the Veta Madre. A Big Fan' Posi- tion of the Orebodies. A Cross-Section. Hum- boldt's Description. What is a True Vein? . .211 The Development of Metallurgical Practice at the Sirena Mill. From Amalgamation to Cyanida- tion. Re-Grinding 229 31. Method of Treatment in the Bustos Mill. Conveying the Tailing by Pipe. The Stamp-Mill. Cyanide Practice. Comparison with the Patio Process 12. Old Methods. An Abandoned Arrastre. The Ha- cienda de Rocha. Men and Mules . . 33- The Flood at Guanajuato. The Humor and the Tragedy of It. Conclusion 252 239 246 xu tut of miustratlons The Gateway Frontispiece Map of Mexico FacingPage On the East River, New York . . 2 New York, as Seen from the Harbor ....... The Morro, Havana. Making Drawn- Work i-i Mexico '. 4 Central Park and Albesu Theatre, Havana ] 5 The Harbor of Havana 6 Cabaiias Castle, Opposite Havana ' , A Glimpse of Old Havana 10 The Prado, Havana . . 11 Orizaba On the Railroad above Maltrata j. Tropical Vegetation 14 A Coffee Plantation ! ! is A Maguey Plantation 20 The Patio of the Iturbide. The Plaza at Orizata ! '. .21 The Palace of Chapultepec . 22 The Chii-ch of Guadalupe .2^ A Country House in Mexico 26 Popocatepetl A Fruit Vendor • • i ' . ! 28 On the Presa at Guanajuato. A Glimpse of Chapultepec '. 29 The Casa Blanca, at El Oro The Timber Camp of the El Oro Mining and Railway Co 3 s Statue to the Last of the Aztec Kings ^5 Sorting Ore. On the Outskirts of Guanajuato 4.: Putting Timbers in Place ' ^5 A Good Lode in the El Oro Mire ........ aj xiii -a_- '^^,:-m.^i.':r'^.- LIST OF ILLUSTRATIONS Facing Page A Rich Stope in the Esperanza Mine 52 General View of El Oro S3 In the Market Place ^ Another Market Place ^' Cyanide Vats and Tailing- Wheel 68 Interior of the El Oro Stamp-Mill 69 Leaching- Vats of the El Oro Mill 76 Blaisdell Excavator and Sand- Vats 17 Timbering in the El Oro Mine. An Old Water-Carrier . . 84 Electrical Traction Underground in the Esperanza Mine . 85 Timbering a Drift-Stope in the El Oro Mine 85 General \'iew of El Oro 92 The Esperanza Mine and Mill 93 The Water-Carrier or Botero 9^ The Cross near the Somera Shaft 99 Pay-Day at the Casa Blanca, El Oro 99 General View of Pachuca "° The Plaza of Pachuca m The Mines of Pachuca "-^ The Mines of Pachuca "9 An Old Patio in Action '22 A Chilean Mill in Operation 123 El Camonero. Moving Slime onto the Patio 134 A Tube-Mill in the Hacienda La Union at Pachuca . . .134 Two Views of the Patio Process '35 Three Stages in the Patio Process 138 Horses Treading the Charge. El Camonero I39 A Typical Patio '46 Mixing the Charge on the Patio I47 Furnace for Retorting Amalgam 'S^ Two Views of Men Operating the Planilla at Pachuca . .159 The Flying Buttresses of San Miguel de Rayas .... 166 In the Courtyard of the Rayas Mine 167 Looking Down the Main Street of Guanajuato . . . 170 xiv LIST OF ILLUSTRATIONS Facing Page The City of Guanajuato 171 Among Friends at Guanajuato 176 Steel Ore-Bins and Battery Foundations of the Bustos Mill . 177 The Gateway of the Rayas Mine 178 The Ruins of the San Miguel de Rayas Mine .... 179 The Great Shaft of the Valenciana, Looking Down . . . 190 Bridge over the Guanajuato River, near La Presa . .191 Two Views of the Tiro General 192 The Tiro General or Valenciana Shaft 193 A Malacate or Horse-Whim 196 On the Road to the Mines 197 A Bit of Old Mexico 198 A Distant View of Guanajuato. The Villas of the Presa . 199 The Basket Store. By the Way 202 Shrine in the Peregrina Mine 203 Hacienda San Francisco de Pastita 203 A Big Slope in the Peregrina Min,. 204 Sorting Ore at the Peregrina Mine 205 Guanajuato 212 A Typical Street in Guanajuato 213 A Bit of the Veta Madre 220 A Mexican Ox Wagon 221 The Tanateros. On the Street 228 Mexican Miners at Work 229 The Hacienda San Francisco de Pastita 236 A Glimpse of Guanajuato Through a Hedge of Organ Cactus 237 Pipe-Line for Conveying Tailirf. Tube-Mill at Pachuca . 242 A Mexican Family 243 Water Wheel and Irrigation Method 246 An Old Arrastre 247 Hacienda de Rocha 250 T)T)ical Hacienda de Beneficio or Reduction Works . . .251 Scenes in Guanajuato After the Flood 254 Plazuela de San Pedro, Guanajuato 255 XV i TCul of TOrawlttjjs Figure Page 1. Cross-Section Through Shaft of the Mexico Mine . 37 2. Cross-Section of Vein in the Mexico Mine . ■ • 39 3. Diagram Showing the Series of Geological Events 45 4. Lode-Fault, San Rafael Vein 47 5. The Esperanza Fault. After J. E. Spurr .... 49 6. Plan of Second Level of Esperanza Mine .... 51 7. Diagram of Cyanide Treatment at Plant No. 2 . . 57 8. Diagram of Sizing Tests at Mill No. 2 .... 74 9. Drift Timbering 82 10. Timbering in Bad Ground 83 11. Use of Jack- Screw 83 12. Special Shaft Set ; 14-in. Timbers 85 13. Square Set. 8-in. Timbers. Plan and Elevation . . 86 14. Square Set. 8-in. Timbers. Elevation and Details 87 15. Split Switch, for Electric Motor Underground . . 90 16. Fixed Switch in Track Underground 91 17. The Santa Inez Vein 125 18. Cross-Section of the Veta Madre 212 19. C. s-Fault of the Veta Madre 213 20. Plan and Sections of the Veta Madre 215 21. Typical Section of the Veta Madre 218 22. Arrangement of Classifiers 233 23. Old Stamp-Mill 248 24 and 25. Arrastre and Pans 249 26 and 27. Retorting the Amalgam 251 XVI ^CW#' . 3W8%JTT * -«r£'^^^F5"«Er'r^:i^'Tt5^iw^ / ^ftllnes of !Jtt exlco Chapter t NEW YORK FROM THE HARBOR — A FAREWELL TO MANHATTAN. HE tide was sweeping down the channel as the Seguranfa left her berth at the Brooklyn wharf and swung into the East river. It was a clear sunny morn- ing early in October and the great harbor of New York lor. .:d its very best. «^ ^^ - - To the sound of many whistles our steamship threaded her way among the ferry-boats and barges that congregate where, off Governor's island, the estuary separating Long island from Manhattan meets the waters of 1'ie Hudson. As we passed between Fort William and the statue of Liberty, the broken sky-line of New York City stood silhouetted against the sky. There ,if.va^^^^mmii^r^ aTi«'»^ AMONG THE MIXES OF MEXICO was just enough smoke to soften the outlines of the serrated pile of lofty buildings, which, like a Titan's stronghold, guard the great waterway. Knowing the manifold activities that have created the island city, I felt the impressiveness, rather than the poetry, of the scene. Even such smoke as came from the tall towers of steel and stone, called, with grim humor, the 'sky-scrapers,' seemed, not the incense rising from a peaceful dwelling, but the murk of battle, the con- fused black fog of complex strife. Despite her higher mental activities and benevolent endeavors. New York, rising proudly by the waters that made her a great seaport, is the expression in stone of a relent- less materialism, a predatory finance, and a reckless luxury of life. Even the statue of Liberty, with her bronze oxidized to green and her guano-crowned head, has the air more of an old woman holding aloft a hot penny to incite a scramble among the awaiting small boys, than of the representative of a freedom long since changed to license. As the Seguranga turned into mid-channel we could see the dark canon of Broadway and the series of splendid structures that line its sunless depth. Trinity church is no longer to be seen, it is obscured by a 23-story sky-scraper where congregate daily a group of men capable of running a continent — and they do their best. The financiers look down upon, and over, the spire of Trinity — in more senses than one. When Huxley came to America, in 1876, he, like all visitors, was impressed with the scene pre- 1 NEW YORK HARBOR 3 sented even by the undeveloped New York of that day, and seeing the yellow dome of the World build- mg, which for so long dominated the high roofs of the aty he exclaimed that in approaching the shores of other lands, the first thing to be seen was a church- steeple, but that here, emblematic of the unshackled thought of a new country, the first to catch the eye was the tower of a newspaper. If he had only known for what literary sewage that yellow dome stood sentry, he, though an agnostic, would have longed to see the old-fashioned landmark. Trinity steeple is dwarfed by the Empire building, but, in compensation, the dome of the World building is hidden by several recent monuments to the growth of our steel in- its tht '^V'7 '' ^f '" ""^ '^^^'' ^'•°^'"& dim amid Brnnwf K . '""^ u'' '^' '"""^^''^^ ^^ ^^e crowds at Brooklyn bridge, the foul air of the Subway the .s and, the .hi.e hulls of the battleships at anchor off th. rio'*^'' '"'" P'"'^*' of ^ handsome yacht, he ^ low processmn of barges crossing to Brooklyn the stately sadmg ships preparing fori long voyage and the majestic movement of a huge Atlantic fee; throbbmg hfe, the pulsations of which are felt the world over. And so. farewell, thou Empress City o 4 AMONG THE MINES OF MEXICO the New World, thou hast the respect received by those that have power, and the admiration due to those that are magnificent; if thou dost not win the love awakened by kindly deeds and homely service, thou reckest not. Men may come and men may go, as long as steel is strong and gold is good ! # l*L M 1 c "^VJL: 9 copter 2 HAVANA— A CIGAR FACTORY— THE SPANISH CON- QUEST— HERNANDO CORTEZ— THE FIRST SIGHT OF ORIZABA. T was four days to Havana. The port is guarded by the Morro, a castellated fort stand- ing on a promontory to tht left of the entrance. During the late Spanish-American war, Morro castle was often busy, but it diH no execution until the last da> , in fact, after the armistice had been signed at Porto Rico. On that soHtary occasion a shell went through the New Orleans, a cruiser, from stern to bow, between decks, killing no one, but playing sad havoc with the officers' quarters. Within the harbor, one is still reminded of the late unpleasantness by the remains of the sunken battleship Maine. The military mast and a portion of the 'strong-backs,' or iron super- structure, project above the water. To them I saw attached a metallic wreath on which was inscribed M^mori Missouri, evidently placed there by the men of another battleship. The Maine was blown up on Feb- ruary 16, 1898, and I recollect the stir it made in dis- tant lands, for on that day I happened to be at Cairo, Egypt, where everyone in the Anglo-American col- ra M T^ -arti-:^7-=3:j-^.< TZZ^ :T> 6 AMONG THE MINES OF MEXICO ony confidently accepted the tragedy as the fore- runner of war. There have been many discussions as to the responsibility for the crime, but it is generally accepted among the well-informed that it rests upon the 'partidc revolucionario, the revolutionary party in Cuba, whose object it was to embroil the United States in war with the Spanish Government. How well they succeeded, all the world knows. I shall not try to give any account of Cuba, even at second hand, for is it not told, and told well, by Robert T. Hill, whose 'Cuba and Porto Rico,' is a monument to his insight and industry. Cuba is a lovely island, about the size of New York State, covered by good soil and possessing a wonderful variety of eco- nomic resources. Only 10 per cent of the island is cultivated; in the valleys of the western hill-country is grown the tobacco that has done so much to soothe mankind, to express the courtesy of the civilized, and to promote the 'riendship of the thoughtful. Natu- rally, I went to a cigar factory and bought some real Havana cigars on the spot, fresh from the making. In a large rooiu about a hundred men sat in rows before small tables, like school-boys' desks. They were wrapping the tobacco leaf into cigar form. As they worked, a man standing on a stool read to them from the daily paper; he read dramatically and well, the purpose being to keep th» workers interested. The proprietors of such estabMshments encourage this practice, which is general, because the men do not talk while the reading proceeds. When a Span- a;^ u ■r. SANITATION AT HAVANA 7 jard talks he uses his hands in gesture, hence he can not employ them in labor; therefore the reading en- courages efficiency. The men pay 10 cents per week from their wages ($J per day) to the reader, who, in large establishments, makes as much as $125 per month. Most travelers have spoken of the unhealthiness of Havana, of the dirt and filth that force their contrast with its beauty and color. Whatever criticism may be passed, by an unfriendly historian, on the Ameri- can interference with Cuban aflfairs, it is certain that the sanitary measures undertaken after the war have wrought wonderful improvement. Garcia, Palma, even Sampson and Schley, were great men, but greater than these were George Waring and Leon- ard Wood, who did more for civilization than the leaders of war. And theirs was a contest with dan- gers as great as co.. . to those on the battlefield, for Waring died, the victim of the yellow fever that he almost eradicated. But Havana interested me most as a link in the story of Spanish conquest. Hernando Cortez, after outfitting at Santiago, called at the port of Havana before starting upon his great quest, on Frhruary 10, 1519. His fleet consisted of eleven vessels, more than half of them open brigantines, and the biggest not to be rated at over 100 tons. Thence he went to the coast of Yucatan, making a halt at the island of Cozumel, before proceeding to the mainland of Mexico. He landed at Vera Cruz on April 21. We t AMONG THE MINES OF MEXICO followed nearly in this course, for from Havana we went to Progreso. the port of Menda, which is the chief Jty of Yucatan, and from there we also went to Vera Cruz-as did Cortez-on our way to Mexico City The parallel served to emphasize the differ- ence Cortez and his buccaneers went through un- charted seas and to a land they knew only by rumor; to them the West was full of an unlocked mystery and the place of untold gold; to us there was keen interest and expectation also, but it was an mterest toned by experience and an expectation limited by knowledge. However, even the conquistadores can have had no more discomfort or have used language more picturesque than the passengers of the Seguran^a when we lay ofi Progreso for three days at the mercy of a 'norther,' or north wind, which pre- vented the captain from unloading his cargo or com- ing to anchor. Progreso is an open roadstead, and when the north wind bio--, the Irhters that tranship the cargo of the larger steamers are afraid to leave the shelter of the wharf; hence wearisome delays such as ours. And when the sea calmed it was pain- ful to watch the uninttlligent manner in which un- loading proceeded. Among other consignments there was one of 40,000 bricks; the passengers, eager to see the steamer on her way, watching the wretched peones removing this cargo from the hold, s'.ffered with an impatience only to be surpassed by the mor- tification of the consignee, who must have paid heavily for his bricks only to receive them m a badly HiM IMl MINING IN CUBA battered conditjon. Don't ship brick from New York to Yucatan! Between New York and Vera Cruz we saw no mines; nevertheless, it will be interesting to refer to certain facts of history. The first of these islands (afterward called the West Indies) to be colonized was Hispaniola, subsequently known as Hayti and Santo Domingo. The great admiral, Columbus, had discovered it in 1492 and it was he that named it 'Little Spain.' At Isabella and Santo Domingo were founded the first settlements maoe by Europeans in the New World. Hispaniola was rich in gold, for the early records make frequent mention of the mines; these were the Buena Ventura placers and other diggings in the Cibao region where the forced labor of natives was employed, often in a cruel man- ner, to wash the gravel. Spanish estimates of the production — according to my friend, F. Lynwood Garrison — range from $200,000 to a million dollars per annum during the first quarter of the sixteenth century. The chief mining towns were Cotui and La Vega ; as far as can be judged, the gold came chiefly from the erosion of small stringers in the diorite of the Cibao range. It was the impoverishment of these mines that led to the colonization of Cuba. This island had been named Juana, and then Fernandina, but the Indian name has survived all the Spanish christenings. Cortez was a member of the expedition sent by Velasquez, the governor of Hispaniola, to conquer w lO AMONG THE MINES OF MEXICO Cuba, in 1511. Subsequently, but before he invaded Mexico, he was one of those that secured an estate there, living on his plantation and introducing some of the first of the cattle that were brought to Cuba. It is interesting to note that Cortez settled at St. Jago, a name since corrupted to Santiago. He is said to have worked for gold within his domain, the deposits promising better than those of Hispaniola. But Cuba never produced much gold; it is true that the first Spaniards found the natives in possession of personal ornaments made of gold, but these repre- sented the metal gathered in small quantity and dur- ing a long period. The extermination of the aborigi- nes prevented their tyrants from learning anything about the source of the metal. Since that day Cuba has won a position as a mineral region, but this is due to her deposits of iron and manganese, together with those of copper, which occur within a few miles of Santiago, where Cortez was alcalde. Across the bay, in the mountains of Cobre, are the ancient mines whence the great conquistador derived both his gold and copper. The development of these deposits has been revived since the Spanish-American war and it is to be hoped that they will become the basis of steady industry. At last, three days overdue, we arrived within sight of the Mexican mainland. It was a sunny morn- ing, with a breeze raising white caps on the sea and moving masses of cloud from off the dark bank on the western horizon that marked the land of the Aztecs. FIRST SIGHT OF ORIZABA „ Clouds obscured the view, mountains loomed to the no th.^rd. and among them the gleam of snow; ver cT \'"" '^°"' ^" *^^ "hite building of V era Cruz makmg a brilliant fringe along the here. But there was no sight of Orizaba, the vol he fl T^T";^''^^ '''' ^'^'^' -hich rises from the flats behmd Vera Cruz and forms a great land mark m th,s part of Mexico. Borrowing a tel s ope 1 could d.stmguish. over the dancing blue waves the yellow strand of St. Juan de Ulua and behTndk the Cruz. The white wmgs of fishing boats came into he picture, and northward foreft-clad mountl^s TnoJ^TtJ' '''"'' °' '"'^ ^"'"'"'^^ crested whh ••^M^l ^^ 12 AMONG THE MINES OF MEXICO or inspired a poet. It seemed so high a1 all meaner things, rising sheer from the sea, t .iter- vening flat layers of mist emphasizing the height, while the brilliant sunlight upon the snowfields made it appear closer than the lowlands at the base. In a way, it reminded me of my first view of the Southern Alps of New Zealand, as seen one morning on board ship coming from Tasmania, when the serrated peaks flanked by pine forests rose above the troublous dark green waves following in the wake of a storm. But in that picture there was a series of high crests; here, there was one in solitary grandeur and without a peer. Scenes such as these compensate for the dis- comforts of travel and afford a stock of impressions from which one can draw on dark days and in restful hours, when the mem.ory harks back to the past, as to the refrain of some sweet song. ;-.:k" '•'i".,-"' -:^rM\: ^-^ — Ti ■' ■ '-: e^y'^'cCryfJ (ri)apUr 3 VERA CRUZ — ON THE MEXICAN RAILWAY — Tr.OPICAI VEGETATION— COFFEE PLANTATIONS— AT ORIZABA. ERA CRUZ is not the dirty city it used to be; the streets are cleaner than formerly, and the erection of new wharves and quays gives the incoming trav- eler an excellent impression. But the back streets and by-ways are not salubrious, nor does the ever present buzzard suggest pleasant imaginings. These hideous carrion birds are seen everywhere, flopping about in the streets, perched on roofs, even dominat- ing telegraph poles; nay, their foul black shapes ob- scure the blue canopy and desecrate the majesty of Orizaba. If you arrive in the morning on the way to Mexico City, you can leave Vera Cruz in the afternoon, so as to reach the town of Orizaba by dinner time. In this way, escaping from the coast and going to an altitude of 4,000 feet, the traveler avoids the risk of the calentura, the fever of the tropical lowlands. The journey on the Mexican Railway is one of the won- ders of the world, in respect of scenic beauty and variety of vegetation. At first the train winds 14 AMONG THE MINES OF MEXICO throush sandhills, partly hidden by abundant -revn, and then over marshy ground; but this is only f jr ten miles, when the ascent begins, over the lower plains. Sugar and corn appear; th?n comes a grass country interspersed with scrub and cactus, much like Natal, only the cactus here is in greater variety and instead of anthills the surface is dotted with boulders of dark lava. The train threads its way through rank grass and past frequent hedges of organ cactus ; the scars made by the railroad, even the steepest banks, are entirely healed with verdure. When the locomotive stopped we heard the broken notes of the orache and there was further confirmation of the plentiful bird-life, already suggested by the nests hanging from trees and woven around the cross-bars of telegraph poles. At thirty miles xrom Vera Cruz, near Soledad, the foothills are reached and in this well-watered tract the tropical vegetation is luxuriant in the extreme. The ridges of lava that mark the base of Orizaba are not at all like the Drakensberg, severely bare and drearily rugged, but they are absolutely smothered with rich verdure from foot to crest, and in the canadas or rav'nes now visible, as the train emerges from successive tunnels, there is a foliage of increas- ing gorgeousness. Between Camaron and Cordoba the botanical wealth of the tropics is lavishly dis- played; nature, stimulated by warmth and moisture, has clothed the earth with splendor. There are the scarlet hibiscus, purple bougainvillea, the lavender '.;'^. TROPICAL VEGETATION IS plumbago, crimson oleander, pink azaleas, the yellow and red flags of the coleus, even magnificent orchids, with creepers of eveiy shade of green festoonmg the forest . ... Soon the train passes coffee plantations. The wild undergrowth has been cleared, but the larger trees are left in place, so as to give shade to the coffee shrubs (five to six feet high), which are planted between them. The young coffee shrub is delicate and must be protected from the direct rays of the sun for at least two years; maturity is attained in the fourth year. The plants live 25 years and require compara- tively little care— less than sugar, for instance. Speaking of these matters, it may be noted that chocolate is indigenous to Mexico and the word itself comes direct from the Aztec chocolatl' ; nevertheless, Mexico nowadays imports chocolate from Guatemala and Caracas. Shade is imperative for the young coffee plant ; in many cases it is cultivated under the protection of banana pilms. This is the practice also •The Aztec languaRe is still spoken by a million people, chiefly in the S ates o Puebla, Jalisco, and a part of Vera Cruz; U .s a semr- flictionaT language like 'the Maya in Yucatan. The Otomje " ab^'-J e X different from the Aztec; it is monosyllabic and Pf"^^^ '/, °'f L-a' ' spoken by less than half a million people, chiefly m '^e States of Hidalgo. Queretaro, and Mexico. Otomie in structure J,«embles Chmese and. indeed, it has been claimed that the modern Chinese immigrant an make himself understood among the Otomie Indians, but this, ao 1 was told by Don Carlos de Landero, is neither vera nor ben trpvato It is a mere philological analogy." However, the perpetuation o* these ancient tongues is an interesting fact. Occasionally .t is a nuisance be- cause of the difficulty of transmitting intelligence. At 11 O™- *°^ "" ample, there are a number of men working underground th?.' do not under- stand Spanish or its Mexican variation, and they have tv> be shown what to do by signs. l6 AMONG THE MINES OF MEXICO fl in Ecuador, Peru, and Brazil. It is said that the best coffee in the world comes from the famous Youngar valley, in Brazil, where it is grown in an old ceme- tery under bananas. The yield is only a few quintals per year, but this coffee fetches enormous prices. As a rule the small berries (canicalilla) are preferred, but the Youngar coffee is of large grain. Owing, how- ever, to rankness of verdure, many of the Mexican plantations looked so overgrown as, by reason also of the trees retained for sheltering the coffee, to seem like the bush primeval. Soon we saw the yellow gleam of oranges and limes amid dark foliage; picturesque hamlets ap- peared, with red-tiled roofs and thatched houses, and white-clad peasants. At the railway stations there was always a crowd of fruit-sellers; bunciics of roses and magnificent bouquets of gardenias were purchasable for a song. But the panorama of life and color suf- fered eclipse as the darkness of the tropical night came suddenly, without any intervening twilight. We lost the famous view of the f^arranca de Metlac, but even in the dim starlight I made out the outlines of the curved steel bridge, as the train swung round it; there was the gleam of the torrent below, a feel- ing of space and dark void, with the lights of dwell- ings far away. For the town of Orizaba most travelers have a kindly feeling, because it brings the first sleep on shore after the sea voyage, it means a good dinner at the Trand Hotel de France and a perfect cup of coffee TFIE MALTRATA VALLEY »7 made from berries prown near the neighboring town of Cordoba. Early breakfast in a patio (courtyard) bowercd by bougainvillca, to the music of a fountain, gave the bracing morning air a perfume and a fra- grance long to be remembered. The mountain is vis- ible from the town, but the view is not impressive. On resuming the train journey, we were soon climbing a heavy grade, circling the famous Maltrata valley and ascending 4,(XXJ feet more in a distance of 30 miles. One looks down over precipitous slopes of vivid green along narrow gorges that lead to a valley cradled among the onlooking mountains and check- ered \.- . squares of cultivation The little huts and the clusters of trees look li\. playthings of a doll's house, infinitely far away „ "d quite detached from the busy life that throbs through the train with every effort of the locomotive. This view of Maltrata bears some resemblance to that obtained when de- scending from the upper to the middle plateau of the Drakensberg, Pietermaritzburg taking the place of Maltrata. /^ ij J I t Chapter 4 11 THE PHYSIOGRAPHY OF MEXICO-OUTLINES OF HISTORY — AT ESPERANZA — THE MAGUEY AND PULQUE — A NATIONAL HABIT — ARRIVAL AT THE CITY OF MEXICO. S everybody ought to know, the interior of Mexico is a high plateau enclosed within moun- tains of volcanic origin; this plateau rises suddenly from the lowlands that fringe the east- ern coast; it is bounded west- ward by the Sierra Madre mountains, a part of the American cordillera, on the farther slope of which there is a sudden descent to the coastal plains of the Pacific. In traveling from Vera Cruz to Mexico City, a part of this structure is made manifest. The tierra caliente, or warm lowlands, forms a narrow strip, to which succeeds the temperate zone or tiena templada, b'^twfien 3,000 and 6,000 feet above sea-level; then, by abrupt ascent, one comes into the tierra fria or cold country of the high tableland, at an altitude of 6,000 to 8,000 feet. Any rigor of climate such as might be due to a high altitude is tempered by the latitude, so that Mexico City, at 7,349 feet, and a little south of ^ ■■ OUTLINES OF HISTORY 19 Lat. 20° North, has a temperature ranging between 60 and 75° F. the year round. Mexico is 1,950 miles in greatest length, from north-northwest to south-southeast; her northern frontier is 1,500 miles long, while at the isthmus of Tehuantepec the breadth of land has narrowed to a neck of 130 miles, separating the two oceans. A few dates will recall the history of the country. Cortez and his company of adventurers captured the City of Mexico in August, 1521. Three hundred years of Spanish government, varied by revolutions, ensued. In 1810 the people finally revolted against Spanish domination and after an internecine strife of eleven years, independence was gained. Iturbide, in command of the insurgent troops, marched into Mexico City on September 21, 1821. It was almost exactly three centuries since Hernando Cortez made his triumphal entry. In 1821 Mexico owned an enor- mous territory; besides the lands of the present Repub- lic, she ruled Guatemala, and to the north all that part of the United States (up to Canada) which is west of the Red and Arkansas rivers. Much of this domain was lost as the result of the war with the United States in 1846 and 1847. Peace was made by the treaty of Guadalupe Hidalgo in 1848. In the territory ceded at that time was the whole of the Rocky Moun- tain region and California. I have never seen it re- marked that while this treaty was signed on February 2, 1848, the first discovery of gold, by James W. Mar- shall, at Coloma, was made on the January 19 pre- ao AMONG THE MINES OF MEXICO ti 1^ ceding, or two weeks earlier. Mexico did not know what she was losing and the United States did not know what they were gaining. It is certain that had the goldfields of California remained under Mexican rule during the days of early discovery and prolific production, there would have been complications, into which the European governments might readily have been drawn by reason of the magnitude of the prize at stake. It was fortunate indeed that Califor- nia became United States territory before her mineral wealth had aroused the greed of the nations. To return to our story ; we had seen Maltrata and had reached Esperanza, 8,044 feet above sea-level. Here the plateau extends with a sandy severity re- minding one of parts of Arizona; from the moist air of Hie tropics we had passed into the dusty winds of me highlands. To the north, Orizaba hid his great head under a panoply of cloud and over the brown plains to the west were the white summits of Popo- catepetl ('the smoking mountain') and Ixtaccihuatl ('the white woman'). Thib part of Mexico is largely given to the cultivation of the maguey or aloe, the agave Mexkana. Just beyond Apam the valley widens, be- coming one immense plantation of maguey, reaching in ordered sequence and in lines of mathematical reg- larity to the dark hills in the south. The accompan ing photograph illustrates the appearance of such plantation. Maguey is the plant the fermented sap oi which yields pulque, the national drink of the Mexican. mmq. i . mma THE MAKING OF PULQUE ai It is the 'century plar ' which got its name from the i(^ea that it blooms once in a hundred years; which is true enough in one sense, but the maguey does not bloom each one hundred years or at the end of one hundred years. It matures in seven years; at that time the central shoot springs up with extraor- dinary rapidity to a height of six or eight feet, and blossoms. But when cultivated as the source of pulque, this flowering of the plant is not permitted; as soon as the stem gives evidence of emergence, it is cut at the basal socket, so as to form a bowl in which L.'llects the sap intended for the nourishment of the gigantic stem we associate with the 'century plant.' If the incision for the removal of the heart of the plant is done too soon or too late, it dies unproductive. The sap oozes into the socket and is removed twice a day at first, and then each morning. It collects at the rate of one to two gallons per day until, after about three weeks of tapping, the plant is exhausted. In extract- ing the sap, a slender gourd is used as a siphon; the operator places one end in the bowl and the other in his mouth, then he draws the sap into the gourd and pours it into a sheepskin bottle. These bottles are emptied into a pigskin bag, for loading onto the mules and burros that carry the liquor to the hacienda or farm, where it ferments over night, so as to be ready for transport to the City early next morning. In the course of travel this liquid intoxicant gains the smell of the untanned raw pigskin, acquiring a filthy odor, 22 AMONG THE MINES OF MEXICO 'I I {^ so that the pulquerias or saloons at which it is sold give forth a noisome stench. It is the whisky of Mexico and when fresh it is said to be nalatable. To me it seemed to have a smell compounded of sour milk and tainted meat ; it is good only (if at any time) when ab- solutely fresh, that is, when drunk in the locality where it is gathered. Mescal and tequila are other alco- holic products of the maguey; they are derived from the distillation of the roots. From the heavy pointed leaves, five to eight feet long, the Aztec made the paper on which his picture-writings were recorded. The modern Mexican uses the fibres of the leaf, after the plant has been exhausted as the source of pulque, to make twine {pita) and rope. With it he also makes the ayate or coarse cloth in which earth, corn, pro- visions, almost everything, is packed for transport on his own or his mule's back; for instance, the pigskin bag holding the pulque is held in an ayate. It is said that 1,300,000 pesos' are spent each month in Mexico City for pulque, mescal, and tequila. It is recognized by physicians and other thoughtful men that the drinking of pulque is demoralizmg both physically and mentally. (So also is whisky, es- pecially bad whisky. An observant Mexican would find abundant cause for commenting upon the demor- alization of the American and Englishman that soak themselves with poor whisky and make fortunes for 'Throughout these pages the Mexican currency will be expressed in terms of pesos and ccntavos, while the gold standard will be expressed in terms of 'dollars' and 'cents.' One dollar is roughly equal to two pesos. wmmmm bC'i.-toLf.. ■Hi .tX^^'jU.-. TSfV •.'■if I -/Zt S^ f ft If % .1 i% \^ \ THE ADMINISTRATION OF DIAZ 23 the distillers.) Efforts have been made to curb the habit by moving the pulquerias farther from the centre of the City. The chief obstacle to such regulation is the long leases held by these drinking-places. Barley and i.orn, probably wheat also, could be grown on the land now devoted to the maguey. In these cereals the country cannot supply the needs of the population. The duty on wheat was reduced for three months in 1905 by reason of the scarcity of flour and the hacendados tried to put up prices by creating a 'corner.' In such matters as these President Diaz is enlightened; he abominates strikes and is opposed to monopolies injurious to the community ; although there is one glaring exception to his usual methods. I refer, of course, to dynamite, in which commodity a monopoly has been legalized. This is the weak spot in his administration; r >me of his personal friends, and even his son, are interested in the concession that has been so hurtful to the mining interests. We reached Mexico City after dark, but the bril- liantly lighted streets and crowded thoroughfares gave an impression of pleasurable life. That night I heard a splendid band (of the police) in the patio oi the Iturbide hotel, playing in honor of the convention of American railway passenger agents. The volume of inspiriting music awakened every corner of the building, which was once Iturbide's palace. But if the first Mexican emperor had revisited the glimpses of the moon, he would have bent his head with shame. ^ ^ jy • £±witm'm'"i ix«.^i»/^T .iirs.?^' ■ 'r^s^'-'msti'.- i 24 AMONG THE MINES OF MEXICO On the second floor, there is a corner room that once held a shrine; it was Iturbide's chapel, and now it is a trunk-room wherein are deposited the multitudi- nous wares of itinerant Chicago drummers! Es triste. It reminded me of Kingsley's words, inscribed upon the drop-curtain of the Tabor Opera House at Denver: i; "So fleet the works of man, back to the earth again ; Ancient and holy things fade like a dream." (ri)af ter 5 GEOLOGY ALONG THE RAILROAD — PRECIOUS METALS IN THE VOLCANIC DUST — VEIN FORMA- TION—THE SULPHUR OF POPOCATEPETL. HERE was not much geology to be deciphered along the railroad from Vera Cruz to Mexico City, except the wonderful construct- ive features to which the Sierra Madre Oriental and the great Mexican table-land owe their origin. The plains of the coast are made of Tertiary sedimentaries, from the actual dunes of the shore to the foothills of the Sierra Madre, where the railroad enters the Middle Cretaceous, the rocks of which are largely covered by the lava emitted from young volcanoes. At Penuela there is a quarry of Middle Cretaceous limestone, which is the stone em- ployed in building the mole and breakwater at Vera Cruz. Coming west, between Maltrata and Boca del Monte, the railroad cuttings expose intensely folded strata, traversed by faults that divide the Cretaceous series in step-like succession. Above Boca del Monte, the sedim^- t ries are crowned by remnants of lava streams and volcanic dust, in part consolidated as tuff and in part loose earth, but hardly warranting the idea a6 AMONG THE MINES OF Mi XICO once prevalent that these deposits Iiid been accumu- lated by wind or, in geological phrase, were of eolian oripii'. ""'hrough this volcanic material, ummocks of the ' re.; ceous make an appearanc as at San Andreas. I'll- :■ st of the journey to Mexuo City is lade over i'laUH broken by occasional rocky domes and car- petet: with volcanic scoria, tuf? nd -nalpais.' Such a IT ('in of olcanic dust is oitin termed 'ash.' A?*- is the product of combustion; ti is mat. ria! is the re- sult I ! v:)lent explosion and fragmentary ejection from tlic > cnt of a volcano; it is lava that has been torn into bits hy the expansive force of steam, formed by release pressure. It is, therefore, 'dust,' that is, minutely subdivided rock This material, call it what you may, is of interest to the miner, because (Ccasion- ally, when mixed with the products o the df..ay - '" other more ancient rocks, it carries gold. Near Jalapa a large area is aid to give assays of one to four grams of gold per metr ■ ton^f 2,204 pounds. Two erams is claimed to be ar; aver- ;e, and .is this material cya nides readily, it may become commercially valuable. An analogous occurrence is found in the ma; ve vol- canic rocks i the ranges northwest ' Mex where both the precious metals exist ing - _ -i fissuring, to the extent of one or tw< ;ram gi'old and nine grams of silver per ton. T: e met.. is tiavc 'This is the word th.it in its corrupted for- malarai, is used .Arizona and ihc Southwest Kencrally. tci that he wrote as a sort of protest against the injus. . done to him, in calling the new metal after the Sc. n~ dmavian goddess instead of— for example— Riita. For his was the discovery. In the museum there are some fine meteorites- one specimen weighs 14 tons; it came from Chihua- hua Another, called the San Gregorio mass, has in- scribed upon it the following Spanish rhyme: Solo Dies Con zu-Poder Este fierro destxuira Per ce en cl Mundo no Abra Quien lo pueda Dsfaccr. I trust no scholar, critical of the Spanish of this quotation, will impute its apparent errors to me I give the words exactly as I copied them from the mscnption Which may be interpreted: "Only God with his power can destroy this iron, for there is no one in the world who is able to unmake it." It was discovered in the year 1600 and weighs 10,000 kilo- fn^'n Jn'^'i'^' '"^'''^^ '' ^^""^ ^^^ San Gregorio, >n the De Allende district of Chihuahua. fh.r ^Y observatory on top of the building there ,s a splendid view of the city and its environs Z'T^'^'^'f' ^^"' '^' ^^^^"-^ °f the cathedral and he domes of the churches of the Profeso and Santa Teresa nse finely above the multitudinous II 32 AMONG THE MINES OF MEXICO buildings, cut into squares by straight streets, beyond which are the dark foothills dominated in the dis- tance by the broken crest of Ixtaccihuatl and the big cone of Popocatepetl. To the southeast, one can see Iztapalapan — now Istapalapa — where, on the eighth of November, in 1519, Hernando Cortez met Monte- zuma, and the pioneer of European invasion ex- changed courtesies with the poor king whom he so utterly destroyed within less than a year. At that time Iztapalapan was a place of twelve thousand houses and it was under the rule of Cuitla- hua, the brother of Montezuma. Through the town passed one of the three great causeways that led across the lake to the City of Mexico itself, and it was over this causeway that the Spanish adventurers made their way. Today Istapalapa is a small village and where once spread the waters of the lake, there is marshy ground. The causeway is obliterated by a modern street, that of Acequia, which took advan- tage of the secure footing thus afforded. It starts from the portals of the Plaza de la Constitucion, as does also, in the opposite direction, northward, the San Andreas street, which merges with the road to Atzeapotzalco; this was the line of the causeway to Tlacopan or Tacuba along which the Spaniards re- treated on the occp.-ion of the Noche Uriste, that black night of July 1, 1520, which saw them all but anni- hilated by the fury of the Aztec pop" 'ace. At Po- potla the survivors halted under a ; that exists ii^M •jvi'^s'^y THE BATTLE OF OTUMBA 33 to this day. It is now guarded by an iron railing, but despite even this protection it is endangered, for I read in the daily paper, during my visit, of the arrest of a vandal, who wanted a piece of the bark to add to his collection of curios. If ever there was a time in the Spanish conquest when Cortez and his fellow pirates were heroes indeed, it was just after their sad halt at Popotla. Of the number that had entered the City only a third (250) of the Spaniards survived and of their native auxiliaries only one fifth (1,000). They had lost most of their horses, all their bMtillery, all their muskets, so that there remained only their swords and their courage. But Cortez faced the music like a man and was confident even in the hour of deepest gloom. Scarcely one week later, on the plain of Otumba, this handful of men met a multitude of natives, estimated all the way up to 200,000, and beat them off the field, mainly by reason of the desperate resolve of a few of the cavaliers, who followed the immediate lead of Cortez and penetrated the thick of the combat in order to kill the chieftains on the opposite side. It may have been comparable to the attack of a centre-rush of a senior football team mto the midst of a kindergarten, but it was rend^^red magnificent by reason of the astonishing disparuy of numbers and it proved abundantly that the superiority of race was not due to physical strength alone. It is a fact, both significant and pathetic, that K>.':-^. /I ! 34 AMONG THE MINES OF MEXICO while there are today several statues to the last Aztec king— Guatemotzin or Cuitlahuac— more par- ticularly the fine monument in the Paseo de Reforma, and while nearly every city in Mexico has a bust of Hidalgo, the priest who started the final revolution against Spanish rule, there is no statue to Cortez in the whole length and breadth of Mexico. I ! I ^ ^9magF-"]g^m^, The TiMiim Ca.mh or thk Hi. Dkm Mining & Railway Co (TlKiptftr 7 EL ORO-RICH MINES -THE GEOI OGY OR tuv: ROM Mexico City I went to El Oro. This mining district is 90 miles northwest, and while most of it is within the State of Mexico, its northern portion ex- tends into the adjoining State of Michoacan. At the time of my visit (October, 1905) El Oro was attractmg much attention; a new orebody in the Esperanza had s. - .p the shares (of the company owning that min • ••, , ondon; El Oro Mining 1^ Ra^^ay Company ...r.. b.d risen in sympathy:!) * Es^rdlas was makm., . boor . market in Mexico Cu and Vu:tona y Ane . ,v.. fluctuating in a n»^an.-; beloved of speculators. As a foundation u. .' ,o" •"? .''''^'^'■^^' ^ ^^""d 'odes of unusua. ^eo-" ef n ed" h^' '"'/ metallurgical practice thatfe^ resented the sum of great technical ability. 1 le mmes are situated on the slopes of a ride-e un tTT '"^ ^'^^^^ *^^ -"^^' through wS way On th""" '"^ ^' '""^ ^'^^'''^" N^*--' Rail- way. On the near (eastern) side are the Mexico, %' ''^ iTi H I 36 AMONG THE MINES OF MEXICO Esperanza and El Oro mines; on the farther slope is the Dos Estrellas. The three mines first men- tioned follow a series of veins of which the San Rafael is chief; these dip into the mountam. The Dos Estrellas, on the other side, also dips to the west. The bush-covered summits of the ridge consist of an andesiie lava, while the mine workings are mainly m shale. A covering several hundred feet thick of (probably Pliocene) andesite is spread over the an- cient eroded surface of a (probably late Cretaceous) shale, in which occurs a series of quartz lodes, con- taining gold and silver. The cap-rock forms part of an extensive extrusion of volcanic material, the main vent of which is not known; although in the mines there have been encountered tongues and irregular bodies of the same rock, suggesting many minor places of emission. The shale is thinly laminated, black, and calcareous; it contains occasional layers of limestone. According to Robert T. Hill, it is the formation in which occur many of the best mining districts of Mexico. The relation of the cap-rock, the shale, and the quartz lodes is seen best in the Mexico mine, which, being a young property, is easily accessible throughout. The accompanying cross- section (Fig. 1) through the main shaft is based upon a tracing given to me by Mr. Fergus L. Allan, super- intendent of the mine. The shaft goes through the andesite of the cap- rock for nearly 600 feet and then penetrates the shale. After passing through this shale for 450 feet, the ^i 41 iiiia I SrvTi > rn TiiK l.vsT tiF tmi A/tkc Kim GEOLOGIC FORMATIONS 37 E3 0l.!)t« ANOf'jlTE Fto. 1. Cioss-Section Tbioucu Mai» Shaft of xue Mcxic» Mirrt (I ]! u ^ \MONG THE MINES OF MEXICO •' ters andesite and continues in that rock to . item, just below the sixth level. This v - desite, in the foot-wall country, is the same rock as the cap; it is evidently younger than the vein and, therefore, later than the other andesite, w' ich over- hangs the San Rafael vein, as seen in the first four levels west of the shaft. Some distance west of the San Rafael vein, in the Nolan mine, narrow intrusions of this younger andesite have been found running at right angles to the course of the vein. The deeper levels have not found the older andesite on the hang- ing wall; it antedates the vein, for mineralization extends into it. The same tongue of andesite occurs in the northern workings of the Esperanz;-. and m a similar position relative to the vein. In some places ore has been found in this andesite, where it is ad- jacent to an orebody in the vein. The lode consists of banded quartz, built mainly of rock in place, which has been shattered and silicified, the whole body attaining a width of 30 to 50 feet. The ore occurs in streaks parallel to the walls of the vein, in some places combiniiifr and oc- cupying the larger part of the space between. This quartz contains just enough iron oxide to color it; when banded it is always good, the poor portions of the vein being characterize 1 by massive white quartz. The shale adjoining the loJe is bent and shattered; it shows numerous streaks and small veins lying parallel to, and running into, the main vein. That portion of the vein which is found at the old surface .L -i ^w THE VEIN IN THE MEXICO MINE 39 Fic. 2 Cuoss-StcrioN or Veim w thi Mexico J ! S 40 AMONG THE MINES OF MEXICO of the shale has a width of 30 to 40 feet ; it had evi- dently undergone erosion before being covered by the later flow of andesite. As a rule, where the apex has been thus exposed to weathering, the San Rafael vein is richer than usual; it has undergone a note- worthy concentration. In the southern portion of the Mexico mine the apex of the vein is found at the surface of the shale, but farther north the vein comes to an end 100 to 250 feet below the old surface of the shale. When the vein does not reach the old sur- face, it frays out into stringers, bent over at their ends, as shown in Fig. 2. The particular vein shown in this sketch carries an average assay-value (11 dwt. gold and 6 oz. silver) right from the start; it widens until, at the fourth level, there is 20 feet of quartz; on the second level, only 25 feet above its blind apex, there is no indication whatever of the proximity of a lode. The conditions just described as occurring in the Mexico mine are found in the Esperanza and F.l Oro workings, which extend in sequence southward. As seen in the El Oro mi.ie, the veins leally con- stitute one big lode-channel with portions of country between, that is, the distinction between what is ore and what is worthless quartz is purely commercial, based on assays, and not upon geological and struc- tural distinctions. At first the Branch vein, one member of the system, was found to be rich enough to exploit; then a smaller sireak on the hanging wall of the big Main vein (the San Rafael) was vvorked. THE EL ORO VEINS 4» and finally the foot-wall portion of the San Rafael was stoped, to be followed by the exploitation of various subordinate nr ibers of the series, as they were determined to be rich enough in gold and silver to more than defray the costs of mining and milling. A typical cross-section of the lode-channel shows sundry branch veins, then the foot-wall orebody of 35 feet, then streaks up to three feet wide between the foot-wall ore and that of the hanging, which is 40 feet wide; finally, beyond these there is the Branch vein, 5 to 18 feet wide. At the north end of the mine the orebodies of the foot and hanging are separate; they come together in a distance of 700 feet and form one width of 80 feet, which is maintained nearly to the south end of the shoot,, in the vicinity of the incline shaft. The ore on the hanging is fairly uniform in value across n?. f'.i'! widtS, but the foot-wall ore is best on the li.m^iiig si !-, even after they unite the individuality of ' streaks is maintained. When the bands of ricli re in this mine terminate, they do so first by narrowing, and then by the splitting or fanning out ol the mass of quartz that contains them. Divergent streaks connect the various orebodies, and some of them are rich enough to be stoped. The whole lode- channel is interrupted at intervals by a succession of faults dipping at 65 to 70°, except the southernmost or diagonal break, which is 35" ; all of them dip north. Water was first struck in the El Oro mine at 425 to 430 feet below the cap — for all measurements are 1; 4> AMONG THE MINES OF MEXICO li made from this old surface. Maximum water was encountered at 1,200 feet. The Somera shaft began to show a heavy inflow between 786 and 1,000 feet, especially from 900 feet down; the water entered along stringers on the hanging-wall side of the lode. At 1,000 feet, the cross-cut (90 feet long) to the lode cut more water along other veins, so that when the lode was finally struck there was no great addition to the inflow. The water in the workings on the main lode remained ai the 786-foot level until the lode itself was cut at 1,000 feet. The faults appear to be impervious and serve as barriers; each block has tu be drained separately. At the end of the rainy season, surface-water makes itself felt in the mine, but only in the northern workings, where it seeps down through cracks in the cap-rock caused by mining operations, more particularly the large stopes on the San Rafael lode made by the Esperanza and El Oro companies near their common boundary. The rainfall apparently does not affect the inflow of water in the deep workings, the mine-water (except in the case above noted) having no direct connection with the surface. (ri)af>Ur $ GEOLOGY OF THE ESPERANZA MINE — INTEREST- ING STRUCTURE — A BIG FAULT — RICH OREBODY — STORY OF THE DISCOVERY — CHARACTER OF THE ORE. N the Mexico and EI Oro mines there is some geology, which is not particularly complicated, but the ground between, ocupied by the Esperanza mine, presents many intricate problems. There is a good deal of geology in the Esperanza, and there is a good deal of rich ore. The geological fea- tures have been carefully studied by Mr. J. E. Sjmrr, and the data embodied in my notes are largely the result of his work, in association with the manage- ment. The accoinpanying diagrams (Fig. 3, 4, and 5), and the geological plan of the second level, as given in Fig. 6, are based on sketches and a blue print given to me by Mr. W. E. Hindry, the manager. To him and to Mr. W. H. Haynes, the assistant manager, I am much indebted. The main geological events, the results of which are evident in the mine workings, are : 1. The deposition of the shale. ({ ! M 44 AMONG THE MINES OF MEXICO 2. Intrusion of andesite in the form < dikes and sills. 3. Faulting, involving several dislocations, one of which became the channel of the San Rafael lode; and later movements that displaced the lode. 4. Deposition of ore by waters circulating along the channels made by the previous fracturing. 5. Intrusion of a later andesite that overflowed at surface and penetrated the shale formation. 6. Cross-faults. In Fig. 3 the San Rafael lode is shown as seen in cross-section, looking northwest, in the northern por- tion of the mine. The sequence of geological events is indicated by the numbers 1 to 5. First, the shale was ruptured and dislocated at least 1,000 feet— from 1 to 2. Then it was eroded and on it was spread the andesite, the original surface of which (at 4) was reduced by erosion to the present surface (at 5). The thickness of this andesite cap ranges now from nothing up to 700 feet. In the meanwhile the intru- sions oi earlier andesite were also faulted with the shale, as is suggested by a tongue of that rock indi- cated on the diagram. In Fig. 4 the same sequence is exhibited as is seen in a cross-section of the southern end of the mine. In this case a higher intrusion of earlier andesite is shown and also a tongue of later andesite. The lode, therefore, follows a big fault; but it is itself faulted, as shown in Fig. 5, which is a longi- tudinal projection N 60° E, magnetic. On the first SimriNi; ( )hk 1 I K \ / ^ - i • * O.N riiK ( » IT-'KIKTS UK (ir \N.Ml'ATO MICROCOPY RESOLUTION TEST CHART ANSI and ISO TEST CHART No 2i 1.0 I.I IIM 132 iT 1^' 1.25 iu 2.5 2.2 2.0 1.8 1.6 ^ APPLIED IIVMGE Inc C^b'! ^Si - 0500 - Pfi.- I ( I : »1 ' -i H ; ii r I A BIG FAULT 45 »4'».w«> **4«t Mv»r4t^ Fig. 3. Diac:rau Showing the Sesies of Geological Events That Brought Abouv the Present Structure. Cross-Section of nosthekn portion of esperanza mine. 1 ^ {J ;(< II 46 AMONG THE MINES OF MEXICO level at a point 525 feet north of the El Oro boundary, this fault cuts through the country and displaces it, as measured by broken ends of intruded older an- desite, 500 feet vertically. This same fault is evident at the surface of the shale (now buried under later andesite), for there is a drop of 160 feet in the bottom of the cap-rock. This would appear to indicate that the moven^ent transverse to the lode continued after tHe later andesite overflow, so that in the main fault, the total dislocation is measured in two parts, two- thirds or about 340 feet of which occurred before the cap-rock was formed, and one-third, or 160 feet, after that event. In the mine the lateral displacement of the San Rafael lode is 130 feet, to the right. At the south shaft the cap is 284 feet thick; near the north shaft it is 165 feet higher (by reason of the rise in the ground in a length of 1,600 feet, which is the distance be- tween the shafts) plus the fault (160 feet), plus the elevation, making the present thickness 165 -f 160 4- 284, or 609 feet. South of the fault the lode is en- tirely in shale all the way down to the fifth level; just below that horizon there is andesite on the foot-wall and shale on the hanging. North of the fault, the first level penetrates cap-rock, while the second has shale on the foot and the older andesite on the hangii.g. The third and fourth levels repeat the conditions observed on the second. At the fifth (still north of the fault) there is a change; at about 100 feet in the foot-wall the newer andesite (which is Putting Timbers in Place COMPLEX GEOLOGY 47 the cap-rock) appears at a point 500 feet north of the fault and thence to the boundary of the Mexico mine. At the sixth level the older andesite is seen in the foot- wall south of the fault and looks like the top of an Fig. 4. Lode-Fault, San Rafael Vein. Cross-Section of Southern Portion of Esperanza Mine. intrusion; north of the fault, shale appears on both foot and hanging, that is to say, we have the condi- tions which exist south of the fault 500 feet overhead — this being the measure of the dislocation. On the i n 48 AMONG THE MINES OF MEXICO seventh level the older andesite appears along thj foot-wall up to the fault, shale showing in the hang- ing. North of the fault the lode is in shale as regards both walls, with the newer andesite in the foot-wall country (150 feet east of the lode) near the Mexico boundary. At this same level — th seventh — the newer andesite (or cap porphyry) '' s in the form of an east-west dike, 153 feet thick > a point 825 feet west of the lode, but its real shape has not been ascertained. All this refers to the San Rafael, the main lode of the Mexico, Esperanza, and El Oro mines. The interesting problem, at the time of my visit, was whether the new West vein is faulted (see Fig. 6) in a manner similar to the San Rafael or whether this bonanza vein is younger than the fault itself. If the latter be the case, the vein would go into the andesite north of the fault at the third, fourth, and fifth levels. The ore of the San Rafael extended up to the fault, the break being clean. At the fifth level pay-ore was broken almost up to the fault-line. The San Rafael is generally more broken on the north side, the ore not reaching up to the fault as clearly as it does on the south side. If the West vein be later than the fault, it is likely to be weak where crossing the latter and probably it will be less rich in the andesite than in the shale, the bonanza portions of the veins of this district being in shale country. With the limited data at my disposal, it seems to me unlikely that the new vein is younger than the fault, because there is Ai. A RICH OREBODY 49 no evidence of its existence in the northern workings. The new Esperanza orebody is a sight to gladden the eyes of a miner. It is 680 feet long, with an average width of 9 feet and an average yield of 75 grams of gold (or $49.70) per ton and 1,150 grams of silver ($19.55) per ton. The shape of it is roughly lenticular; it is widest about the centre and comes nearly to a point both north and south ; in depth it is 1 T.T EsPEBANZA Fauli. After J. E. Spurr. shaped like the bottom of a boat, with protruding keel. Where first cut on the fifth level, there were two veins close together; the first assayed $1.50 to $2 per ton, while the other, or No. 2, to the west, \'ent $75 per ton. Subsequent stoping gave a different story; the No. 2 has been payable only for 50 feet above this level, while the No. 1 gets into rich ore so AMONG THE MINES OF MEXICO f ; f' i n three feet above and only 15 feet south of the cross- cut. At about 45 feet south of the cross-cut, the two veins come together and make a width of 35 feet of ore worth over $100 per ton. The moral is: If you find absolutely nothing by drilling, do not cross-cut ; if you find any encouragement whatever, cross-cut. In the workings that I visited there were slopes four feet wide of ore worth $500 per ton ; where the quartz was rich, even the adjoining shale (penetrated by small stringers of quartz) wis good enough to stope, for it assayed 15 to 40 grams c'' gold.* Small bands of shale included by the vein assayed equally with the quartz. It seemed to me that, as compared with the San Rafael lode, this bonanza vein was particularly well defined; there was no gouge and the ehale at the walls was broken off clean, without shattering or twisting, the bedding of the outer country ly .ig flatly right up to the ore. The vein is apparently younger than the San Rafael, because there are few signs of later movement, such as slips or gouge-seams. The ore itself is beautifully ribboned ; minute crystals of pyrite incrust the quartz, especially in geodes or vups; the richest ore is mosceado^ that is, speckled with argentite. On the seventh level there is an interesting vein occurrence ; this is a seam of pyrite called the 'sulphide 'A gram of gold is worth 66.4 cents and a gram of silver 17c. My description of the 'rebody is based, it mast be remembered, on notes made at the end r October, 1905. 'From mos a fly. m^'^-ikii^ GEOLOGY OF THE ESPERANZA MINE 51 "1? &' W . S bos;" bji I* S .SOB o ..» g S M O "Spa .9 I HI: J^g-s s.s Sa AMONG THE MINES OF MEXICO t ^ streak,' 26 inches wide, in the foot of the San Rafael lode, which here is 22 feet wide. The sulphide streak crosses the San Rafael and is therefore younger. The foot-wall country in this part of the mine is porphyry (andesite) and the sulphide streak is built up of brecciated porphyry, the hanging being irregular and penetrated by quartz veinlets, while the foot-wall car- ries a gouge, beneath vhich the fragmentary char- acter of the vein-stuff is evident. This vein carries a pyrite which is coarser than that of the new West vein and in the ratio of !2 per cent; the West vein yields one ton of concentrate to 16 tons of crude ore, that is, over six per cent. In speaking of ore at El Oro as being worth so many dollars, it is meant that it contains so many pennyweights of gold, for the silver is not included. This is largely a habit inherited from the days when the silver was not extracted in commercial quantity. A $7 to $9 (or 7 to 9 dwt.) gold ore will carry $1.50 to $2 (or 2.5 to 3.3 dwt.) silver per ton. The gold is free and in firi particles, rarely visible, while the silver occurs chiefly as the sulphide (argentite), with some chloride in the upper levels. The quartz is extremely hard and flinty, beautifully ribboned in lines parallel to the walls of the lode. In this respect and in its general appearance it often reminded me of the ore produced by the Amethyst and Last Chance mines at Crecde, Coloiado, in 1894. Argentite occurs along the lines of ribboning in minute streaks be- tween seams of opalescent quartz; the natives call • 3 H ■ K^^H ^^^H ^^H-'x lp- ^^H^^Bi r^Mn fl Hi-'^^ .'• ^^^H Bv^^^fl ^^^H B'iw-i^ i H^^H I^Hf^^l ^^^^^^^^■^^H ^HttH J^^^l E jbE^T i' ' ''^ ^^^H ^^^I^H ' ' ' v^^jD ISj """ l^^l nl^ nl ^^^^^^^^H K^^^BE/^H ^^l^^^^^n ^Bl^^ fl HB^M>';''^ ^Hl^^^^Hf ^^QVi> ;J ^^■iffiBfe^ll),. ^^^^EA^^BT^ v^~ 9HH HP.'Trfl ^^^^^H I^B^''^'' il ^^^K^^ ^^DB Sill « H|ft;d ^ n H .\l GOLD PRODUCTION 53 .1 ■1 these hilos, or threads. The ore is largely a replace- ment, by silicification, of the encasing country and this holds true no less of the andesite than the shale. The Esperanza is sending mineralized porphyry to the mill and mineralized shale to he smelter. Beau- tiful pseudomorphs of quartz after calcite are fre- quent, they appear as sharp scalenohedra and re- semble the 'water quartz' of Cripple Creek. The best specimens occur in the small 'horses' (or included fragments of country) within the vein and on the outside of the big pay-streaks. All the surrounding shale shows the "^flfects of mineralizing activity and the outside andesite will often yield traces of metal; for instance, the old decomposed andesite on the fifth level of the Esperanza assayed 0.29 oz. silver and traces of gold. At the time of my visit, at the end of October, 1905, the rate of production of the El Oro district was slightly over $1,000,000 per month, distributed thus: Esperanza, $650,000; Dos Estrellas, $240,000, and El Ore, $200,000. An output of $12,000,000, 82 per cent of it being gold, made El Oro the second most pro- ductive gold-mining centre on the American con- tinent. i i^,f I ip. u n 'I • (Lfyupt^T 9 DEVELOPMENT OF THE MILLING PRACTICE AT EL ORO — BEGINNING OF CYANIDATION — FIRST BIG MILL — CHANGE OF METHOD — TUBE-MILLS AND RE-GRINDING. EVELOPMENTS in the mill- ing practice at El Oro are full of I interest. In 1873 a hacienda de ' beneficio, or reduction plant, was I erected to crush ore and treat the accumulated tailing from a still older arrastre* and to this _ - - _ -_ _ P^ant further addition was made in 1885. The mill then included 25 stamps with amalgamating tables. In 1890 the accumulation of tailing made by the stamps was sold to a man from Eutte, named Albertson. The tailing he handled was richer than the ore being mined today. Never- theless, the contract for the treatment of it was cancelled after the purchaser had installed four amalgamating pans, with settlers, and had started to ship bullion. This was under the regime of General Frisbie. In 1894 a Chilean mill was brought from Chicago, to grind the ore after it had passed through a Comet crusher. The Chilean mill did finer grind- *The Anglicized form is 'arastra,' but there is no need to use it, the Spanish term itself being preferable. mMRmnm Pi AN EARLY CYANIDE PLANT 55 ing than the stamps, which at that time were also preceded by crushers, of the Blake type. The mill in tuin left a dump that, eventually, as methods im- proved, it became profitable to e-treat. Late in 1894, James B. Ha^'gin bought control. In the fol- lowing year the old mule-stable was converted into a cyanide annex. Redwood tanks 24 feet in diameter, with 4>2-foot staves, were erected ; the sump-vats were larger, with 6-foot staves. The tailing was carried, in boxes on the backs of peones and in hand-barrows, to the vats. Cyanide solution was first introduced by upward percolation through a false bottom, the suc- ceeding water-washes being applied from above. This was followed by precipitation on zinc shaving, with acid treatment for the zinc 'shorts,' the bulk of the precipitate being carefully washed and melted forthwith. The bullion thus obtained was of extra- ordinary fineness — 960 to 980 — without the use of any nitre in the melting. This was one of the first successful cyanide plants in Mexico. With only the addition of the small cyanide annex just described, the mine paid $1,000,000 in dividends up to May, 1898, besides meeting the cost of various installations, including part of the 100-stamp mill taken over by the English company, which now controls the prop- erty. The first 100-stamp mill was designed under the Haggin-Frisbie regime and was only expected to crush 4,500 tons per month through a 60-mesh screen. When the property was purchased by the Explora- f ■^■H 56 AMONG THE MINES OF MEXICO 4^ u tion Company in 1898, this mill was too near comple- tion to be altered. The slime-plant was added in 1900, after the present company had been formed. W. K. Betty had conducted a series of experiments for the new owners and double treatment was then adopted for the slime-plant. This was only making the best of conditions as they were found ; hence the pile of stored tailing now about to be re-treated. The general plan of treatment was as follows: From the stamp-battery the pulp passed over copper plates and was then divided, by spitzkasten, into 'coarse sand,' 'fine sand,' and 'slime,' each product receiving individual treatment. The sand underwent double treatment in South African style ; it was first cyanided in collecting-vats and then dropped into cars that removed it to the treatment-vats. The slime was caught in a settling-vat and thence went to the treatment-house, where it was agitated by jets of compressed air. After treatment, the sand was dropped into cars underneath the vat, while the slime was flushed out with water in the ordinary manner. In the meanwhile the capacity of the mine grew, not only by reason of the discovery of new orebodies, but indirectly through the cheapening of operations, so that further enlargement of the mill became prudent. In 190.S another, and the last, addition to the reduction plant was made. The aew mill of 100 stamps, with its up-to-date cyanide equipment, differs from the old one in five respects, namely: .A CYANIDE TREATMENT AT EL ORO 57 ' i'. z':^M!:4i^mim^'m'^--2'^'tmm:^i: ■n^ ':> • I ■: ^ « i 1 > ! 58 AMONG THE MINES OF MEXICO 1. Mechanical handling of the ore. 2. Heavier stamps. 3. Re-grinding in tube-mills. 4. Mechanical handling of sand by distributors, excavators, and belt 5. Mechanical agitation of slime by stirrers and centrifugal pumps. The new mill contains 100 stamps, each weighing 1,180 pounds, falling 102 times per minute, with a 6-inch drop. The depth of discharge is 2>4 to 3 inches with a new die, and 3>4 inches when the die is worn out. Woven brass wire screens of 35 mesh are used. Th- accompanying diagram" (Fig. 7) illustrates the process. From the stamps the crushed ore goes to a system of cone-classifiers and spitzkast .1, which separates the coarsest sand and sends it to the tube- mills for re-grinding. The fine sand from the stamps combines with the similar product from the tube-mills and is elevated by the raff-wheel to the sand-collect- ing vats. Any slime that may have escaped com- plete separation and accompanies the sand, overflows from these vts and passes to the slime-plant, joining with the rest of this product that has been eliminated from the sand by the classifiers. The sand is dis- !i • Borrowed by permission from 'The Grinding of Ore by Tube-Mills, and Cyaniding at El Oro, Mexico,' by G. Caetani and E. Burt. Trans- actions American Institute of Mining Engineers, February, 1906. This is a conscientious and most valuable paper, giving a detailed account of the cyanide practice at El Oro. -^^S"^^^ MECHANICAL DEVICES 59 tributed by a revolving irn jhanism of the Butters & Mein type. There is no chemical treatment in the sand-receiver, the idea being to keep the mill-water free from cyanide while effecting a final separation of slime, so as to get a clean product. The water and slime are drawn off through gates or slots on the side of the vats; these gates are closed by a roll of canvas as the vats fill. The sand, when thus finally freed from the last trace of slime, is removed by a Blaisdell excavator, which drops it through a central opening onto a Robins belt-conveyor. This Blais- dell excavator s like a revolving disc-harrov; and it has proved a most efficient machine, it uses com- paratively little power and works smoothly. The belt-conveyor takes the sand (containing now only from 10 to 11% moisture) to the treatment-vat, which is fed by a revolving distributor operated by a variable-speed nriotor, the centrifugal force being so regulated as to throw the sand to the sides or centre of the vat, as required. The charge is 265 tons, dry weight. Ten washes of alternately medium (0.1%) and strong (0.2%) solution are introduced, six hours apart. This treatment is followed by no less than thirty 'weak' washes, such a lengthy operation being specially designed to extract the silver. These 'weak' washes are four to six hours apart and contain 0.0.3''O cyanide. Each wash is equal to 13 tons of solution. After treatment, the residue, again using the Blaisdell machine, which moves on rails, is dis- f:m^ ::'Qi^- 6o AMONG THE MINES OF MEXICO charged onto a conveyor that takes it to the dump. Here the distribution of tailing is regulated, as the accumulation grows, by a hinged belt-conveyor in two lengths, the last one being swung round accord- ing to the contour of the ground. iih'iiti^^ i»i liii f ,i . J ( . ^ i 3 t- J P 1 i ( CbopUr 10 TREATMENT OF SLIME— USE OF LEAD ACETATE- ADDITION OF LIME — ITS DOUBLE FUNCTION — SETTLEMENT OF THE SLIME — THE TUBE-MILLS - THEIR LINING — SUCCESSFUL WORK. HE slime goes to a collecting vat, from which the thick mud is drawn oflF at the bottom and thrown into one of the treat- ment-vats. There are twelve of ^,.v these, each 34 feet in diameter /^ and 12 feet deep. Here it is agitated with a proper propor tion of cyanide solution, which is introduced simul- taneously. The apparatus for stirring consists of two long and two short arms made of oak. These are solid; they taper outward from a cross-section of 4 by 6 inches to 4 by 4 inches. The thick end is bolted to a steel star, which is set on a ^'ertical shaft. When the vat is charged, lead acetate is added imme- diately. Tests have shown that a beneficial result ensues forthwith, particularly as regards the disso- lution of the silver. Lead salts, when added in excess to the cyanide solution, give a precipitate of basic lead cyaride, but when present in small proportion the lead remains in solution, presumably owing to the formation of yfl 6a AMONG THE MINES OF MEXICO U t an alkaline plumbite (K,PbO,) by reaction with the caustic alkali, thus: PbAc, + 4KOH = K.PbO, + 2KAc + 2H,0. Mercuric chloride is sometimes employed for the same purpose, producing a reaction with the KCy so as to form a soluble double cyanide, thus : Hga. + 4KCy = K,HgCy, f 2KCI. The most useful effect of these soluble lead and mer- cury compounds is the removal, m the form of in- soluble HgS and PbS, of any soluble sulphides that would otherwise retard the solution of gold and silver, and might even re-precipitate silver already dissolved : K,S -I- K,HgCy. = HgS + 4KCy. K,S -I- K,PbO, + 2H,0 = PbS + 4KOH. The double mercuric-potassium cyanide also acts as a solvent, attacking gold more readily than simple KCy; and this action is independent of the presence of oxygen, gold replacing mercury : K^HgCy, -f- Au = KjAuCy^ -f Hg. Silver is similarly dissolved. These reactions have been amply verified. The action of mercurc-potas- sium cyanide on gold is the basis of patents secured by Keith and Hood; the latter also claims the use of lead as facilitating the solvent effect of cyanide solu- tions. De Wilde has a patent involving' addition of lead oxide to the cyanide solution. These compounds also influence precipitation beneficially if they remain in the solution up to the point of entering the zinc- box, as in that case the lead and mercury are precipi- tated on the zinc, forming zinc-lead and zinc-mercury i if CHEMICAL EQUATIONS ^ CO tples of high electro-motive force. In this precipi- ta« on the zinc simply changes places with the mer- cur. or lead, as is also the case when zinc shaving is dipped in lead-acetate solution. The charge is 60 tons (dry weight) of slime; this is mixed with a solution in the proportion of 2>^ solu- tion to 1 of slime, by weight. The solution contains 0.05% cyanide.' Agitation continues for six hours The vat is then filled until there is Sj/i of solution to 1 of slime; this is well stirred and then allowed to settle. Settling and decantation consume eight hours. This part of the process is hastened by the use of lime, which is added to the feed of the tube-mills. The lime has two functions, one of them chemi- cal, the other physical. By virtue of the first it neu- tralizes the sulphuric acid and decomposes the ferric sulphate contained in the ore, and due to oxidation. Such oxidation may have occurred in parts of the lode before it was mined, or it may have been developed by subsequent contact with the air in its passage to the mill or during treatment. The lime serves in this way to protect the cyanide of potassium or sodium, as the case may be. In slaking, the calcium oxide (CaO) takes up water to form the hydroxide (Ca(0H)2), which dissolves in wat?- to the extent of one part in 800. Lime is preferable to caustic soda, 'Sodium c>anide is used, but all calculation? are made in terms of the cqmvaUnt potassium cyanide. lOU lb. NaCy is equal to 128 lb KCy, "?5,"''^^' '" practice eight-tenths of NaCy does the work of one unit of NCy. I he chemical action is the same, the lesser freight on the more cncentrated form of the cyanide making the sodium preferable to the potassium salt. j- v iw 'Jv- ■f I .V « u 64 AMONG THE MINES OF MEXICO for this particular purpose, because the calcium car- bonate is in'ioluble in water, while the sulphate is but slightly sol'.'ble, so that they do not accumulate in the cyanide solution, as is the case with the correspond- ing sodium salts where NaOH is used as the neutral- izing agent. Soluble carbonates are also precipitated by it, leaving caustic alkali in solution, thus: CO3 -(- Ca(OH), = CaCO, + Ufi NajCO, -I- Ca(OH)j = CaCO, -|- 2NaOH. By reason of its physical function in the mill, lime coagulates slime, so as to cause settling of the parti- cles. The effect is complex. Much of the material classed as slime is of a colloid nature; indeed, slime has been recently labeled a 'colloid hydrate.' Such matter when brought into contact with pure water becomes almost gelatinous, and therefore impervious to solution. There are several substances, notably alum, acids, soap, and lime, that, when added to the turbid water, cause the gelatinous matter to coagu- late or flocculate, so as to produce a separation into distinct agglomerations. Further, minute particles of ore, whether slimy or not, if suspended in water and refusing to settle, develop a tendency to subside when lime, alum, and other substances are introduced. Although imperfectly understood, these reactions are used largely both in metallurgy and in agriculture. The slime settles rapidly; within two minutes there is an inch of clear water. Then the clear solu- tion is decanted and passes to a filter-vat, the bottom of which is provided with two or three feet of sand ■ ^^ ^ V ■h i TUBE-MILLS 65 on the top of burlap. This removes any remaining trace of slime, cleaning the solution so that it is fit to go to the precipitation-house. Returning to the treatment-vat; the slime re- maining after decantation undergoes further agita- tion. The vat is filled with a 0.03% solution and agi- tation ensues for 1^ hours. Then follow three more successive washes. The vat is then filled for the fifth time and the mixture is thrown by a centrifugal pump into a deep settling-vat. Five of the treatment- charges go to one of these vats, of which there are six, each being 20 feet deep and 34 feet in diameter, with a capacity of 450 tons. The successive charges from the treatment-vat are fed into one settling-vat until it is full of slime, for as fast as the solution gathers on top it is run ofif, just sufficient time being given for clarification. This clarified solution is so poor in gold and silver that precipitation is not attempted, the solution being used as the first of the washes in the treatment-vat. The new mill contains three tube-mills. All of them were made by Krupp, at Essen. The No. 3 mill is 19 ft. 8 in. long with 3 ft. 11 in. diameter; No. 4 is 4 ft. 11 in. diameter, and 23 ft. 9 in. long, while No. 5 is of the same diameter as the last, but 26 ft. 3 in. Iiing. The smallest of the tubes is found to do most work per horse-power required. In Western Aus- tralia the tubes or grit-mills (as they are often called) have been cut down to a length of 13 feet, but the ore at Kalgoorlie is softer, so that grinding is more ( 1 !' 66 AMONG THE MINES OF MEXICO quickly accomplished than at El Oro. The time re- quired is determined directly by the hardness of the rock, for the ore is fed at the upper end and makes its exit at the lower, through a screen. Of the three types of tube-mill, the Abbe can be filled more than half full; this cannot be r1 ->ne with the Krupp mill be- cause it both fills and discharges at the centre. The Davidsen has central feed but peripheral discharge, while in the Abbe mi's this is reversed, the feed being peripheral and the discharge central. The last men- tioned is built in divisions and the driving is done on tires and by gears, which circle the exterior of the shell, like a Bruckner furnace. The Krupp tube is made of wrought-iron sheets, welded ; it runs on trun- nions placed at one end, so that the shell does not come into play as regards the driving of the machine. The lining of tube-mills is an important matter. Chilled cast iron, both that imported from Krupp's works and that made by the El Oro company itself, has been tried ; the latter costing one half the former and giv* g equal wear weigh t-for-weight. Krupp's lining is from Ji to I inch thick; El Oro lining is Ij^-inch thick. Nevertheless, it is the intention of the manager' to substitute silex, a natural flint with characteristic conchoidal fracture; it is whittled into shape in Germany before shipment, arriving in pieces Zyz to 4 in. thick, 4 in. wide, and 6 in. long. The peb- • Robert M. Raymond, to whom I am indebted for much valuable information, and for a persona! kindness it is not possible adequately to acknowledge. LINING OF TUBE-MILLS 67 bles that do the grinding come from the coast of Den- mark. They vary in size from that of an egg to that of a fist, the average being about three inches in diameter. They w^ear well, six pounds of pebble being abraded during the grinding of one ton of sand; the consumption of lining being 1.6 pounds. [Since then the abrasion has been decreased to one pound per ton of sand.] An attempt is being made to select some of the flinty quartz, such as occurs in the low- grade ore of the mine, to serve as grinding material. This seems wise; if the hard portions of the ore can be used to grind the soft, the economy is obvious. [According to later advices, this was not a success, I also learn that the lining of silex has been discarded in favor of bar plates.] At the time of my visit. No. 3 tube was being driven at the rate of 31 revolutions per minute, while No. 4 and No. 5 made 29 revolutions. The duty of the individual tube-mills cannot be stated; 172 tons of the coarsest sand from the new 100-stamp mill is re-ground from 35 mesh to 150 mesh, or finer, by the three tubes. In addition, 85 tons per day of the coarsest of the 40-mesh sand coming from the old 100-stamp mill is reduced to the same condition, making the total work of the three tubes 257 tons. The tube-mills get everything above 150 mesh, as separated by classification in cones. The aim is to grind to 150 mesh and this is accomplished as nearly as the capacity of the plant will permit. Any oversize is returned — as already described — to be H- \ i i '.. ft-' 68 AMONG THE MINES OF MEXICO re-ground. The cyanide treatment is based on mak- ing a product of sand as nearly 150 mesh as possible, while the 200-mesh pulp and finer are treated as slime. This tube-mill practice has steadily gained in im- portance, the tendency being to treat a larger propor- tion of the product from the stamps and to augment their crushing capacity, while enlarging the cyanide annex. This is a proper way of meeting the neces- sities of a mine the output of which increases in ton- nage as the assay-value declines. The following statement of the work done during the month previous to my visit explains itself: REPORT OF CYANIDE DEPARTMENT, SEPTEMBER, 190S. Mill No. 1. . Gold . . SiWei • Assay* Indi> Atsiy. Indi- value cated value cated Claasificatioii. Tons per extrac* per extrac. treated. ton. tion. ton, tion. % $ % $ % Coarse Sand ...29.23 2,552 9.46 54 33 1.73 27.17 Fine Sand 25.57 2,233 7.86 72.14 1.57 45.86 Slime 45.20 3.947 9.04 93.58 2.03 82.26 Total 100 8,732 8.86 76.50 1.83 58.99 The old mill was built before re-grinding was adopted. The fine sand is poorer than the coarse because it contains less gold open to attack. The slime is richer in silver because of the presence of argentite. Mill No. 2. % Tons. $ 7c $ % Sand 24.12 2.527 8.28 83.94 1.59 65.41 Slime 75.88 7.949 7.68 92.45 1.64 78.05 Total IOC 10,476 7.82 90.28 1.63 75.08 The new mill includes a systematic scheme of re-grinding, as shown by the increased proportion of slime. A better extraction on slime raises the general result to a satisfactory figure. !| I \ Cyaniue-Vats ami Taii.inc.-W !f.F-L jiI I. i ^ . M is ! Mi chapter U FURTHER NOTES ON EL ORO PRACTICE — THE STAMP-MILL — MORTARS AND GUIDES — APPA- Ri\TUS FOR SIZING -THE PRECIPITATION HOUSE -FILTER-PRESSES — RECORD CF TESTS. FEW scattered notes on the El Oro mill may be worth record- ing. The bolts of the battery- frames are coupled by washers; these are 6 to 10 inches long and from 2^ to 3 inches wide; they connect two bolts and hold them firm. If one gets loose, the other holds it in grip and prevents movement. The ac- companying photograph* of the interior of the mill will aid the description. The guides are made at the company's foundry, of cast iron; instead of being sectional, with bolts, they consist of one solid piece. Each stamp has its own guide and a right-angle plate, to keep it in proper place and line. The wear is slight and therefore the stamp works smoothly; there is less heating than with wooden guides. The mortar is a development of the anvil-block. This is an excellent mode of construction, if properly done. I know of one case — not in Mexico — where 'For many of my photographs of El Oro I am indebted to Mr Alexander Anderson. I i' II 70 AMONG THE MINES OF MEXICO f !H trouble was caused by the an.il-block being con- structed so that it did not rest perfectly true on the cement foundation; to remedy this, it was the custom to shim the concrete block with a little cement; when this last broke and crumbled, there was a movement of the mortar itself. At El Oro, the mortar-block is made extra heavy, beet ning to some extent an anvil in itself, with a base three feet wide and a bottom 13 inches thick; this is placed upon a concrete founda- tion, with a piece of quarter-inch rubber belt between. At El Oro, cones are superior to spitzkasten; the sizing tests have proved this abundantly, the separation by the cones being much sharper. The circulation and agitation of slime are aided by six pumps, which are the Butters modification of the Gwynne pump, such as is used in the London dock- yards. They are of the c. .itrifugal type ; compressed air is introduced to effect aeration of the solution. The chief advantage of t»"j Butters modification is that all wearing parts are readily removable. Each pump makes 1,300 revolutions per minute and in that period handles 4>^ tons (SYi tons being solution) of slime. The vats are all made of steel plates, A inch thick on the sides, with 34-inch bottoms. Redwood laid down at El Oro comes to the same cost, but the steel is more durable and makes a tighter vat in a climate such as that of central Mexico. The vat does not dry if empty, there are no staves to check, and there is no absorption of solution. m ZINC SHAVING 7» In the precipitation-house, there is used a device introduced independently by W. K. Beity in South Africa and by Alfred F. Main at El Oro;* I refer to a drop-drip of cyanide {lyzVv solution) over the head compartment of each zinc-box that is precipitating from the weakest solution, namely, the one coming from the treatment of slime. This drip makes the zinc more active, so that a precipitation of precious metal is obtained in a manner usually unattainable from so weak a solution, that is, one containing only 0.02% KCy. Still weaker solutions are successfully precipitated in which the quantity of cyanide is so small as not to be detected by the ordinary silver nitrate test. The method of dipping the zinc shaving in lead acetate (to aid precipitation) is not employed at El Oro because lead acetate is used at another stage of the process, as already explained. Zinc fume was tried, but it was ineffective with such weak solutions. Great care is taken with the zinc shaving, to cut it in thin but tough filaments, not so crinkly as to break easily in handling. The shaving is laid in the boxes most carefully, so as to avoid channeling. The El Oro plant is the only one of its size where acid treat- ment is not used. From the boxes the zinc is sent through launders, to be carefully screened, while it is also being washed with fresh water. Then it is pumped into two filter-presses until they are full, the * .Mr. Main is assistant manager for the El Oro Mining & Railway Company. =7:^R5?tP«'5-, I i i: 1 ■ t \ {' i i ' i . 'it 'i 7» AMONG THE MINES OF MEXICO charge being equivalent to 19,000 ounces of bullion. The effluent solution is returned to the sump, the cakes in the press are washed and then dried by steam, the steam heating the iron of the frame suffi- ciently to dry the cake inside. The cakes are dried to such a consistence as will facilitate fluxing before briquetting; they fall into a car and are then mixed with the fluxes needed for melting; the mixture is fed into a briquetting machine, making round bricks Syz inches thick, 3 inches in diameter. These are dried before being thrown into the melting pot, from which bars of 1,000 ounces are cast. The Mexican work- men are compelled to remove their clothes after work, before passing to the outer room. The precipitation- room has a cemen*^ floor and the furnace has a dust- chamber. The development of milling at El Oro em- phasizes the relative import e of the cyanide annex in the modern wet treatment of precious- metal ore; the annex to the new mill required an expenditure a little more than twice the cost of the new 100-stamp mill itself. The tendency is to in- crease the percentage that is re-ground, the perfec- tion of the extraccion being largely dependent upon the fineness of comminution. At the time of my visit the aim was to make two products; sand, as near 150 mesh as possible (and a decreasing percentage even of that) and slime, that is, all below 200 mesh. Of course, sand, even when re-ground, is different from clay, despitj equality in size of particles; the grains I -^. " .1^ Wt-M- I SIZING TESTS AT EL ORO 7i of 'sand' are sharp as against those of a mud (slime) rendered impalpable by absence of sharp edges. 'Sand,' however fine, filters well, while 'slime' will not filter at all ; it packs like glue. On the other hand, by reason of the relatively larger surface presented by minute particles, chemical action on the precious metals in 'slime' is almost instantaneous. How neceF"ary re-grinding is, was shown by a simple ex- periment made by Mr. S. H. Pearce. Sand, after ordinary cyanide treatment at the old mill, where there is no re-grinding, was dissolved in aqua regia, but the 'purple of Cassius' test, with stannous chloride, gave no precipitate whatever, the gold being effectively locked within the grains of quartz. The assay of the sand gave $4.50 per ton. Hence the need for re-grinding. The accompanying record of tests will prove in- teresting to those engaged in cyanide work. Look- ing at Fig. 8, it will be noted that the legend explains the graphic representation of two sizing tests. At the time of these tests, a 2j^-inch chuck-block was used, but it was too low to have much effect on *he degree of fineness of the product; during the test the stamp-discharge was as through 28 mesh. Under these conditions the load on the tube-mills and on the plant became too heavy, so that finer screens were substituted shortly afterward. In the diagram (taken from the paper by Caetani and Burt, already men- tioned) the ordinates represent the size of the screen and the abscissae the percentage retained on each of -»!' 'I; .\:.;().\(; the mines of Mexico EXTRACTION FROaI SAND 75 the screens. In the legend, "Thro' 250 mesh" should read "through 200 mesh." The use of the term 'sand-index,' to be seen in the note appearing on the diagram, requires explanation. Cactani and Burt employ it, and it represents one of the most valuable features of their paper. The prob- lem may be stated thus: Given two sands of the fol- ';)wing analysis: Mesh On 20 On 40 On 100 On 200 Through 200 On 20 % 7o % ht sand 10 30 25 2nd sand S 15 45 5 15 or slime 30 20 Which of these two sands is the finer? Caetani answers the question from the economic point of view, thus'": It is desired to know the fineness of a sand for the '.ason that the finer the sand, the better the ex- traction obtained. Therefore the maximum possible extraction on a sand of given composition is a number proportional to its fineness, considered from an economic standpoint. As at El Oro the metallurgist can a priori calculate exactly the extraction from a sand when a sizing test has been made, therefore he can calculate the index and represent thereby with one number what would otherwise have to be indicated by a tabulation consisting of 14 numbers. In the examples quoted at the beginning of the paragraph, the second sand is finer than the first, although it contains less slime. " In a letter to the author. C^apUr 12 THE MILL OF THE ESPERANZA — USE OF HUNT- INGTON MILLS — TREATMENT OF SAND — NO AMALGAMATION — EXTRACTION. I* I (i HE Esperanza mill had 120 stamps when the present com- pany took it over, in 1904. It was deemed advisable to in- ' crease the capacity at the least possible cost, so 15 Huntington mills (each of 5-ft. diam.) were , added, with the idea of re-grind- ing before cyanidation. This was tried, but it was found necessary to place the Huntingtons above the stamp-batteries, which necessitated elevating the pulp. It being difficult, therefore, to distribute the pulp to the Huntington mills, it was finally decided to use the latter machines for first grinding, in asso- ciation with, instead of in succession to, the stamps. The crude ore passes over a lJ4-inch grizzly be- fore it reaches the rock-breakers; after being crushed by them, the ore goes over a ^^^-inch grizzly, the un- dersize being allotted to the Huntingtons and the oversize to the stamps. The batteries are provided with 60-mesh screens; while the pulp issuing from the Huntington mills goes through an angle-slot screen i"a ■l! Ill THE ESPERANZA MILL n equivalent to 60 mes' "tily 65 per cent of the product ■will pass 200 mesh. Of the 15 Huntingtons, 6 are now used as first grinders on low-grade sulphide ore, the product be- ing sized and distributed to 6 Wilfley tables, the tail- ing from which, after classification, passes down blanket-sluices before finally reaching the cyanide- vats. The concentrate from the Wilfleys and that washed from the blankets, goes to the smelter at Aguascalientes. The other nine Huntingtons treat oxidized ore, which, after being ground, goes to the cyanide annex. The cost of steel and repairs to wearing parts amounts to 34 centavos per ton; labor averages 15 to 20cv. per ton. The muUer-shells and die-rings are made of rolled steel manufactured by the Midvale Steel Co., of Philadelphia. This is a soft metal and is suscepti- ble of being kept to shape; it can be used until worn out, and is, therefore, economical. Each Huntington mill has its own motor; it has proved itself to be the best n.achine for reducing the ore to a certain point —say, 60 mesh — beyond which, for finer grinding, it is not economical. The sand undergoes treatment for 100 hours; for it is found that extraction ceases then. Aeration is effected by a perforated pipe discharging over the return-solution vat; yet there is no such loss of cya- nide as might have been expected. The former col- lecting-vats are now used for treatment ; there is less aeration and less mixing, but there is a great gain in ;8 AMONG THE MIXES OF MEXICO the capacity of the plant without interference with effective percolation. A vacuum-pump, for with- drawing the enriched solution, is used only at the close of the operation. Sodium cyanide, NaCy, is the chemical employed; it is guaranteed equal to 1257c active KCy, ranging from 124 to 128 per cent. The enriched solution, before precipitation in zinc- boxes, is rarely higher than $2.20 in gold. Fresh cya- nide, in crystals, is added to the heid of the zinc- boxes, sometimes in quantity suffir!ent to keep the solution up to standard strength. There are no amalgamating plates, and no mer- cury is used in the Esperanza plant. This is an inter- esting divergence from El Oro practice. During September, 1905, the output of the mine consisted of 5,280 tons of shipping ore and 12,00J tons of milling ore, having together a value of $780,385. The extraction in the mill was 91.64 per cent of the gold and 52.92 per cent of the silver in the crude ore. At this time the Esperanza was the most pro- ductive gold mii.e in the world, the two ranking next being the Simmer & Jack, with a monthly output of $505,000, and the Robinson, with $450,000; these two mines being in the Transvaal. d)apUr 13 MIXING METHODS IN THE EL ORO MINE — DIA- MOND-DRILLING IN THE ESPERANZA— TIMBERING BAD GROUND — PRECAUTIONS TAKEN — LAYING OF TRACK — EXCELLENT SYSTEM. O time is wasted in handling ore from the El Oro mine. At the main (incline) shaft there are two gyratory (Comet D) crush- ers, the oversize from which goes to a jaw (Reliance) breaker, 9 by 15 inches. Thence the ore passes into bins and from them it is fed onto a (Robins) belt-conveyor, which is made in divisions as demanded by the length (about 200 yards) and the slope to the mill. At the mill the ore is delivered by the conveyor to a traveling tripper which distributes it automatically into the bins; the tripper moves over the bins the entire length of the mill and then returns. When opening up ground previous to stoping, it is the custom to run a main drift in the middle of the hanging-wall orebody, leaving ore on both sides up to the top of the timbers constituting the drift-set. Then stoping begins above the drift for the full width of the orebody. When the ground begins to weaken and re-timbering has been carried as far as practic- 80 AMONG THE MINES OF MEXICO able, the slopes will be about half-way up to the next level; then the drift in the foot-wall orebody is utilized, by driving cross-cuts from it to the hanging. These tap chutes wherever practicable, but if the ground near a chute has caved, then a new raise (from the lateral drift) is made to serve the purpose of extracting ore. Finally, when even the foot-wall begins to be bad, a lateral drift is run in the foot-wall country itself, and this sometimes leads to unsus- pected occurrences of ore. Another procedure is to leave about twenty feet of ore above the top of the hanging-wall drift; the arch of ground being removed upon the final extrac- tion of that block of ore. This method is employed when the maintenance of a roadway is vital, especially when approaching a shaft. It is instructive to note that while the operating expenses at the Esperanza during 1904 represented 74 per cent of the production, after the bonanza was struck the proportion of expenses decreased to 37 per cent. The diamond-drill cut the new West vein in August, 1904, and the discovery was mentioned by Mr. R. T. Bayliss at the El Oro annual meeting in October, 1904, but the big rise in Esperanza shares did not begin until the spring of 1905. The story of the discovery illustrates anew how deceptive a single cross-cut can be. The West vein was cut by a cross- cut on the third level at a point 150 feet north of the south boundary of the nrne; the ore was poor, about 15 inche'- of stufif rssaying 17 grams of gold per ton. 11 THE ESPERANZA BONANZA 8i Next it was intersected in a drill-hole 900 feet north of the place just described, but on the fourth level. Here also it was poor, aL^at 18 inches, assaying 12 grams. This was done by the former Mexican com- pany about four years before the eventual ascertain- ment of its real value. In August, 1904, the drill-hole put out by the new management, at the fifth level, cut the northern portion of the orebody and found 22 feet of an average value of ^37 per ton. But the cross-cut which was started at once on the track of the hole cut an 11-ft. vein assaying $75, the probable explanation being that the drill followed a cross-stringer connect- ing a poor vein, 5 feet thick, to the 11 feet of rich ore, there being 6 feet of shale between them, so that the 22 feet of core assayed $37 per ton. The discovery is creditable to the management, as it was owing to their good judgment in the use of the drill. Now two drills are kept in constant use, although this manner of testing the ground is expen- sive, because the hard quartz abradcL the carbons. The average cost is five pesos per foot of J^-inch core. A Sullivan E drill is used, capable of drillmg 400 feet. In the Esperanza mine, it is the custom to ex- tend main drifts in the ore, which is hard and stands well. Although the shale is softer, it is found eco- nomical to keep within the vein, because this practice obviates timbering as the drift progresses. When the drift has been advanced the desired length — a month's or even two months' work, at 65 to 70 feet per month — the ore is taken down on both sides and I f .1 i>' 82 AMONG THE MINES Oi- MEXICO double drift-sets are put in place. When mining near the big fault, skillful work is required. On the upper levels the shattered ground is narrow, but this evi- dence of faulting increases in depth, so that while it is barely one foot wide on the first level, it is 20 feet I ill Fig. 9. wide at the fifth, where it is dangerous. In order to traverse this ground, not only is 'spiling' required on top, but also on the side of the drift. The set is put in place in the customary manner, with cap, blocking, and 'bridge,' so that it looks like Fig. 9. The 'bridge' serves as a resting place i t ,1 METHODS OF TIMBERING 83 I ■ 84 AMONG THE MINES OF MEXICO I I i 11 for the spiling poles and allows space under- neath for driving. Pointing the spiling up- ward and sharpening it from one side, tends to lift the soft rock. When the spiling has been pushed on top and at sides, it is driven either with a sledge-hammer or, if that is ineffective, with a ram. If the roof- spiling needs this treatment, the ram is put on rollers. This ram is a piece of 8 by 8 inch timber, from 8 to 10 feet long, so as to get a good run with it over rollers; if it is to be used for driving spiling near the floor, the ram is suspended from a roof-timber and thus it gets a swing. If the ground commences to run, the face is bulk-headed with 4 by 12 or 6 by 12 ir planks, according to conditions. These breast-boards are then blocked by spiling, both on top and sides. The next step is to advance them. If the bottom one is advanced first, the ground would run, but if t^.ie top one is pushed, there is nothing to escape, because the top spiling holds it back. There- fore, two jack-screws are brought to the spot and they are placed with heel (or base) on a cross-timber carried by the rear set. The top breast-board is now advanced 8 or 12 inches and a sawed-off block is in- serted within the space thus obtained; this block holds the breast-board in its advanced position. The next board is pushed to a corresponding position, as before; the cavity made is cleared, the soft ground being taken out over the top of the next lower board. This procedure is repeated with the other boards until they are all in line, marking a permanent li I J ; MHB M^i'mim. i TIMBERING IN BAD GROUND 85 advance of 8 or 10 inches or more, as circumstances permit. This is position No. 2, as shown in Fig. 10. On the next advance, longer blocks are used to keep the breast-boards in place and the work goes on until room has been made for another set. See Fig. 1 1. The north shaft is sunk through bad ground, j)articularly a length of 200 feet between the third and fourth levels, and another stretch from the eighth to the ninth. There is a creep of 15 inches per an- Fic. 12. Special Shaft Set; 14-In. Timbers. num, and it is found necessary to renew the timbering every nine months; this is done by a gang of peones si)eciallv trained under a Piedmontese foreman. See Fig. 12.' Double sets are used for timbering main drifts; all the caps are double-locked to prevent splitting and, in rare cases, even the sills are double, when the ground underfoot tends to rise. In such cases an \i U\ ■J t ^■m ii if 86 AMONG THE MINES OF MEXICO Fig. 13. Square Set. 8-In. Timbers. Plak and Elevation. ; ! , i SQUARE SETS 87 I I -r m WSSr.fJ « ■SO 4 -* 4 6 ■c Vf- W \.i. re' Fig. 14. Squahe Set. 8-In. Timbers. Side Elevation and Details. <^^^'^. AMONG THE MINES OF MEXICO 4 ! !■ I ji .! li intervening block of ten inches is inserted, the bottom sill being the first to break. Ordinary sets would last only 60 days, the double sets are in service for 12 months; the top set takes the weight and yields, without interfering with the use of the drift. The lower set remains unimpaired, until finally it is pushed too hard; then the pressure is opposed by the erection of a false set, which, while the lower set is being replaced, does service as a top set. In bad ground it is the custom to leave from three to four inches between the lagging, so as to permit the soft ground to come through, but not enough to block the tram-track. After this the ground is n<- . cased further until the lagging breaks; it is then leplaced by fresh poles. li the weight is from overhead, no effort is made to ease the pressure, which is allovv'cd to break the timbers, to be replaced by fresh sets. The choice is between losing time in cleaning the track or letting the timber stand as long as possible before renewal. It is held that the ques- tion of blocking the track is paramount in a mine pro- ducing so large a tonnage of rich ore. Where it is the intention to encourage the ground to get relief of pressure by pushing through the lagging, the space between poles is six inches. Close lagging requires more frequent renewal, but it eases the timbers. By allowing the side of the drift to break through, more weight is thrown on the timbers, by the enlargement of the arch of ground overhead. Stope-sets are five feet from centre to centre, SYSTEM OF TRACK-LAYING 89 with a height of eight feet. They are so placed as to oppose the tendency of the walls to close, and the consequent strains are all accepted on the end of timbers. See Fig. 13 and 14. Great care is taken with the tracks and ad- mirable system is exhibited in the arrangement of them. The cars weigh 1,100 pounds each and carry 2,200 pounds, the total weight being 3,300 pounds. The gradient is a half of one per cent, that is, it is such that the labor of pushing an empty car up-grade is approximately equal to that of pushing a full car down-grade. The width of track is 23 inch.s, or 60 centimetres, the gauge being based on the metric system. The rails are 20 pounds per yard, and of Carnegie cross-section. The minimum curvature adopted throughout the mine is a \2-it. radius, for which standard cast-iron right and left-handed frogs are used. Switch-points are carefully made in the Esperanza company's own shops; the points them- selves being reduced in a planer instead of the cus- tomary blacksmith shop. All of these precautions tend to assure easy handling of Iieavy cars by in- ferior native labor. Special tools are provided for jending and punching the rails; all curves are laid to template. The ties are 2 to 2^ feet apart and are made of 6 by 8-inch timbers. On curves the gauge is widened lyz inches, and the inside of curves is protected by a guard-rail ; the same protection is pro- vided at the points of all frogs. When using hand- cars, fixed points are l3''1 down; but where electric ill ■■ 1l ] 90 AMONG THE MINES OF MEXICO (1 a w H (A i to A HI SPECIA , SWITCHES 9» r )| 'm 92 AMONG THE MINES OF MEXICO II '! * f •. -I ; motors run, the switches are made movable. See Fig. 15 and 16. The Esperanza company maintains elaborate assay-plans. There is one for each floor in the stopes, the floors being lYz feet apart. On the plan the timber sets are marked in 5-foot squares ; each month's work is indicated by a different color, and in every set the assay-value of each square of ground is marked in figures indicating grams of gold per metric ton. There is no assay for silver because the ratio between the metals is known from experience; in oxidized ore it is dYz grams of silver to 1 gram of gold ; in sulphide ore the proportion is as 15 to 1. Every car loaded with ore from a chute is grab-sampled at the shaft- station, the assays thus obtained giving the average value of the mine-output for that day, while the num- ber of cars gives the quantity. Thus 350 mine- assays are made per diem, and these also enable the foreman to keep a check on the kind of ore being broken. Gangs of samplers, in pairs, test daily each working face in stopes and drifts; a sampler within the space of one set will get a chance to test more than one face, sometimes three of them. Both the moil and the pick are used; the ore is broken onto canvas spread underneath; the samples average 50 pounds apiece and are quartered down to 5 pounds each, before they go to the sampling-room at the assay-office. All these returns are compared with the battery sample from the mill. i I I / I'i * I i I! f ■'r-^^m^'^wmi^wmr. ' JMa^5or^^¥*:\^K£ii^ Cliof Ur 14 row^R-DOS ES^'A^. iMPOSITION- ELECTRIC AXES are heavy at El Oro. They amount, for instance, to 13 per cent on the gross output of the Esperanza mine, but this in- cludes State and Federal taxes, import duties, and the care of trrops stationed in the district. ... , ^ - On bullion the mine pays 21/, oer tne btate. All State taxes are subject to a second r;jzz:' rr ""' ^''^^ ^^^ *° ^^^ ^"-' m!^TZ "u '' ^ ^^^" *^'^' «° "^"<=h for each man on the payroll; there is a stamp-tax on every recorded business transaction; and there are duties on imports, particularly on dynamite Th. ?? ^>'"^'".'t« there is a tax of 243 pesos per ton per month' Th' "p" ''' '''''• °^ '' P^" '« -"'• cases or ^he Esperanza mine consumes m weith °K ^ ■? ""f. '" ''^ ^^^^^' «° that the tax ^:;^^eavily. It ,s intended to compel the mining ^^^^^o^i'^^^^^^^^ the Government, and on removed, while the silver ta"x is r'educej lo'lSt/r cent °" *°''' """ "«" M 94 AMONG THE MINES OF MEXICO v't companies to use the domestic dynamite; but the Mexican company's factory was blown up twice and they had ceased to manufacture at the time of my visit; nevertheless, according to the terms made with the Government, they had to furnish 607o dynamite at 19.34 pesos per case of 50 pounds — a rate fixed by the Government, as against 16.34 pesos, the old price. While the factory was in operation it cost 29.6/ pesos to import the explosive from the United States; the company (Mexican National Dynamite Co.) was furnishing (in October, 1905) American dynamite for 19.34 pesos, but as soon as their factory resumed, it was expected that they would sell their own product at the same price. Americans mining in Mexico con- sider it to be unsafe and usually prefer to import dynamite at 29.67 pesos. Recently, one of the lead- ing companies at El Oro has made arrangements to buy from the monopoly, which furnishes American dynamite at about the same price as paid formerly. The management could not import the American powder direct, however, without paying the increased price. The monopoly is allcwed to charge 16.79 pesos for 40%; 18.07 for 50%; and 19.34 for 60% dynamite. The electric power used at El Oro comes from the Necaxa plant, on the river of that name, 176 miles distant. At the time of my visit the line was nearly completed. It has been built by Canadian capital. Mexico City is supplied from the same power-plant, the distance being 100 miles from the falls to the city . i| POWER TRANSMISSION 95 and 76 miles from there to El Oro, over the wi ^s. There are eight circuits of three wires each between Mexico and Necaxa, and two circuits, also of three wires, from the city to the mines. Fifty thousand volts are delivered at El Oro, by a three-phase sys- tem, and it is expected that there will be a loss of eight per cent as far as the city and an equal loss thence to the mines. The current does not go through a transformer at Mexico. Power is gen- erated under a head of 1,450 feet by a vertical-shaft turbine with the generator on top; the wheel is the invention of Escher Weiss, at Zurich (Switzerland). The hydrostatic head at Necaxa has been obtained by the building of an earth dam, 185 feet high, 1,500 feet thick at the base, and three-fourths of a mile long; it holds 55,000,000 cubic metres of water and backs the river 2^ miles. The transmission cable has a jute core and consists of six strands of No. 6 wire equivalent to No. 000 wire or 0.229 inch. The power is sold to the mining companies on a sliding scale, the prices being graded according to the amount con- sumed, the lowest price being $50 per horse-power per annum to those consuming over 1,000 horse- power. Several times the natives have cut down the wires and stolen them, on two occasions as much as a kilometre bein? removed. This has been exag- gerated by rumoi .o seve i or eight kilometres. As soon as the cables were . ected, a small current (generated by a ftteam-plant at Mexico City) was put on, in order to prevent stealing; the result was that f.fc,_^jcmi ill 96 AMONG THE MINES OF MEXICO Hi several pectes were killed. Later, when one line had a ci,r;* ' rci !?h to distin-^'uish between the «lcad line ard 'h ; li\ one. The copper stolen > cut up md S('' 1 ut lis" lunk shops. ')'i reason of 'he roniaiT.'- of its discovery. J. li. Fournier, its present chit i >' ler, 1- a I'renchman "t education who prospected the surrounding region with much per- sistence. He ff uid 'float' (detached lode-stuflf) where the shale s exposed below the andesite cap and he found similar indicati('ns also in tlie barr.mca (or gulch) at the foot of the mountain. Subse qiiently, he started to work a' 'lie creek-level and ran a long adit to intercept the vem that he believed to be there. At a di^^tai e within the mountain of about 2,000 feet he found it and no mistake. It was tue great Dos Kstrellas lode, Miiich is divided into two veins, one 3 to 5 feet thick, with rich bodies of ore n it, and beyond it ; sother vein 40 feet thick ■ f ^2 d gold ore; the latter i oxidized, but the -ni vein 1- not, except in patches. Tliis resembles the > aditior in the Espcranza, where the new West vein small richer, and unoxidized. while the old Sn: iatael ' wide, poor, and thoroughly oxidized. Fi iruier wa: lonf,' ago regarded as a crazy man, as ha- been the case in several similar instances of persist nt pros- pecting. Thomas Kruse. ^vho discovered tl Drum- ,k1 TME HUMOR OF A CYANIDE PLA T 97 lurnmon K>de, a; .Niarysville, in Montana. v\ rket' alf alone, i I (■ started to sink i win/' and gave it up ; he then commenced ro iU^ a 'tunnf for a upposedly unknown hwJe. ^Vhtn he cut a oig '.idii of '■e, it -ed. b. ? of wa consK! it V IS no* found an out> rop , ni>t : nk a shaft, !> lull v\ hout a- -ista incf ii. ihc procec - :i ^is ■: litarv ' bors, ^\ II the s in< ne ih. gm 11' as 'tool luck. But k nd »i I I The Cks nkak the Somera Shaet Pay-Day at the Casa Blanca, Ei. Oiin LOCAL COLOR 99 prayer, and drops it at the place so designated. On the day of the Holy Cross every cross in the country is decorated with flowers, even artificial ones if others are not procurable. By the heaping of stones at such spots, a cairn is eventually formed, serving as a land- mark. At the place where a priest was killed, near the Somera shaft, there is an enormous pile of stones, as is shown by the accompanying photograph. In the course of a ride on horseback over the surrounding district, on a Sunday, I observed some- thing of the life of the people. There is a notable absence of vehicular traffic; there are no ruts in the roads, which practically are causeways, worn smooth by the sandals and bare feet of the peasants. The paths look as if all the 'weary Willies' in the world had passed that way. The beauty of the scenery and the picturesque coloring of the people is spoilt by the evil smells due to the filthy habits of the peones. At the close of day, when the tropic darkness comes swiftly and the air is suddenly cooled, the Mexicans stalk about silently muffled in their scrapes and with covered mouth, in order not to inhale the air. It is a characteristic of the people that they fear the cold air, largely because they are so poorly nourished as to be easily subject to pneumonia. With their wide- brimmed conical hats, the dirty red blanket or the striped scrape thrown over the shoulder, witii thin shanks and st'^althy gait, the natives stalk about in the gloaming through the narrow street like the brigands of an opera bouffe. There is none of the ' if ' n 100 AMONG THE MINES OF MEXICO I! !;! 1 . breezy swing or the cheerful salutation of the Anglo- Saxon ; nor is this a matter for wonder when one gets to know the miserable life, the petty tyranny, and the scant food that is their lot. Cleanliness, good food, and freedom of opportunity make people more cheer- ful even in a climate less sunny than Mexico. Nothing that I saw in Mexico seemed so pathetic as the conventional acceptance of class distinctions, especially among the women, the sex usually most ager to ape the dress and habits of those who hap- pen to be more favorably placed than themselves. The lowest class wears blue and brown shawls or rebosos, the middle class is distinguished by black rebosos, and the upper class sports the more dainty mantilla or mantle of lace. The most vivid impression that I took away from El Oro was that of a Mexican boy controlling the operat'-n of a sand-distributor through a variable- speed i.iotor. The boy's pay was 75 centavos, or Z7 cents per day, and he had charge of two Blaisdell ex- cavators and the distributor referred to. It was a picture of mechanical ingenuity overcoming a poor labor supply, for it was not the skill of the boy so much as the perfection of the machine that rendered such economy of operation possible. III Cl)apter 15 MINE LABOR — THE CONTRACT SYSTEM — NATIVE IMPROVIDENCE AND SKILL — DIFFERENCE OF LOCALITY — POOR HAMMERMEN, BUT WILLING WORKERS — HOT MINES. EXICANS take kindly to me- chanical labor, such as that of the machine-shop or carpenter- ing. The average native car- 1 penter, who gets from 2 to 4 pesos per day, is as good as the white men of his trade that drift into the country from the north. Timbermen are fairly satisfactory also; they receive two pesos per shift. As a rule, the Mexican is clever with his fingers, as is illustrated in the shaping of statuettes and in weaving. Guadalajara is famous for carved images and Cuernavaca for the manner in which its people mold clay into statuettes and flower- pots. The assay crucibles used in the El Oro mill are made locally; so also are the muffles. The crucibles, sizes F and G, holding two assay-tons, cost only two centavos apiece and give excellent service. The ordinary unskilled laborer— such as is re- quired for carrying material, for unloading, for stack- ing cord-wood, or in excavating for foundations — is paid 50 centavos per day, but it is becoming difficult to get men for such low pay. In a new mining camp I 1 i t '\' i '-f-' 102 AMONG THE MINES OF MEXICO or on the farm, the day laborer is paid only 25 centavos, while in the north, near the border, he gets three pesos. This is owing to the proximity of the American labor supply and the competition between the mining companies, the wages tending to equalize despite the international boundary, because both the northern workmen and the Mexicans go across that line, to and fro. Work underground is done on contract as much as possible; even the trammers and skipmen are em- ployed on this system, prices being set so that the miners earn from 1 to 1.25 pesos per shift. In measuring ground under contract, the unit is a width of two sets (3.4 metres) of timbers, and the pay is so much per metre long for the full height of a set (two metres). Mine contracts are made with each gang of six men or more, the agreement being arranged with the two leaders (one to watch the other) ; and these hire any additional labor such as is needed for remov- ing rock or tramming. Contracts are measured weekly, on Saturday night. Wages also are paid weekly, the surface laborers on Saturday night and the miners on Sunday morning; this frequency of payment being due to the fact that the peones have not enough money to carry them longer than seven days. On Sundays the market is crowded with vendors of corn (maize, from which tortillas are made), beans (the frijoles), vegetables, and fruit. The Mexicans lay in a week's supply; any money remaining is spent on pulque. On Monday they are in a demoralized i Kk i li r 1 y. ■ I. »? THE MEXICAN MINER 103 state. Owing to these customs the laborers lo-- vo days per week regularly, besides an extra 1 .ay (fiesta) each month. But annoying as thes. . li- tions are to an energetic management, they are better than they used to be. Even on local holidays, the pconcs formerly took three days for their celebration, while now one day ordinarily wlli suffice. But there are still seven or eight fiestas in the year when no pretense of working is made, and operations under- ground cease. Of course, these national character- istics of the Mexican do not affect — at least directly — the American workmen; they are paid monthly, and appear to be not only sober in their habits, but also unusually efficient. In different parts of Mexico the skill of the miners will vary; at El Oro it is less than at Pachuca. The cost per ton of ore is not much cheaper than if done by skilled white miners. Mexicans are not miners by instinct; as long as they can maul at a face and detach chips of rock, they will hammer it, instead of picking it loose or putting in a shot. They are wretched hammer-men ; a Cornishman watching them would be inclined to say that it was a "caution," and the American miner would exclaim that it was a "fright." They do not appear .0 have any of that body-swing, when the hand slips over the long handle of the hammer; instead of this, they have a tight grip and strike short blows over the shoulder; they will insist in shortening the handles; nor do they use the pick where obviously it would bring down loose m ilF, ^ . ^- ( i|!i if* ■: jj : } r 1 r T] 104 AMONG THE MINES OF MEXICO ground, but they worry the rock with short hammer- blows delivered with woodpecker persistence. The heads of their hammers get into a woeful condition and their picks are rarely such as a white man would care to own; in general, they appear to take poor care of their tools. Owing to their inability to swing the hammer freely over the shoulder, they cannot drill an 'upper' and therefore they are not much good in a raise ; but they are most expert in a winze. At the south end of the El Oro m.ine, I saw some Mexi- cans sinking a winze below the 286-foot level and they were down over 80 feet on a dip of 65°. All the rock they broke was being carried in sacks on their backs from the bottom of the winze to the level, and they were being paid 15 to 20 pesos per metre for a winze 3 feet wide by 6 feet long. In the Mexico mine, winzes S by 6 feet cost 25 to 30 pesos per metre. The shift-bosses in the Esporanza mine are mostly Italians (Piedmontese); they are among the best miners in the world and learn Spanish readily; in a month they acquire a working knowledge of the language and they seem to know how to manage the peones. Most of the Piedmontese in the Esperanza mine come from Bisbee, Arizona, simply because the foreman worked there at one time. Boys are employed underground for minor tasks, such as doing errands, carrying -attr, and cleaning tracks. They are only 8 to 10 :, ^ rs of age. On the whole, the full-grown workmen .re not well built, they have the physique of a big boy rather than that i rf M 1 • 4 ' 1 ^ m .i m ~ y m U W!^ JJ'V HOT WORKINGS 105 of a mature man; their strength is all in the back, the muscles of which have been developed by generations of burden-carrying. They can transport enormous loads on their shoulders, but are incapable of carrying any weight in their hands. At the Esperanza there are 3,952 men employed; scarcely three per cent are whites. For some tasks it is necessary to use four or five Mexicans to accom- plish what one white man could do, but on other work the Mexican will do what the white man cannot do at all, especially as regards carrying loads. The Mexican will often serve where a mechanical device would cost more. When working in the mines the natives are naked save for a loin cloth and sandals {guaraches), for the air underground is very warm. On the second level of the Mexico mine it was 85°; in the shaft (owing to steam-pipes) fully 1(X)° F. In the cross-cut from the 286-foot level going west from the Somera shaft the temperature was 95°, and in the cross-cut at 1,086 feet, it was up to 105°, by reason of poor ventilation and escaping steam. The general temperature in the workings is 60° to 70°. The heat is due largely to the action of water on the lime in the shale — slaking it — and it may be due also to the crushing of the shale, which is often seen to press heavily on the timbers. At Guanajuato, it is estimated that it takes 2 to 2y2 Mexicans to do the work of one capable white miner, but the native is paid one-fifth the wages given D.i t ^i 1 t I! S ' 1 . ,:t 1 , :j lii ■'11 m io6 AMONG THE MINES OF MEXICO to the other. The men seen in the mines are under- sized, they have the physical proportions of an American boy. In the mountainous regions, as in Durango, the miners are bigger and stronger, and on contract work they can earn twice as much as the Guanajuatenses. Owing to fiestas, it is found that in employing a gang of peones on such work as excava- tion, it is necessary to carry 100 men on the payroll in order to have 30 Iways available, that is, they work one-third time. By a town ordinance the miners are compelled to put on trousers before appearing in the streets. In coming up or going down a shaft the tanateros sing alabanzas (or hymns) in rough time; it is a sort of chanty. In drilling a 'down' hole, there is no difference worth mentioning between white and native labor; the Mexicans strike the drill 100 times per minute, and their short rapid blows will equal in final effective- ness the long body swing and harder blow, made on»-half as fast, of the European or American. The Mexicans work in less space. I have seen 18 men working in a shaft 7 by 15 ft.; there were nine pairs, one man holding the drill and the other striking, the change of one to the task of the other being made with the celerity characterizing a drilling contest. They carry water for the hole in their mouths and squirt it out as it is required. Like the Turk, the native Mexican is a great porter. In carrying weights, the load is hung by a A STRIKE AT GUANAJUATO 107 rope attached to a head-piece (mecapal), which is a nearly oval mat made of the ixile fibre; it takes the shape of the forehead, and reaches down to the eyes, lying over the front hair and under the hat. The tarUeros, or ore-bearers, can carry eight arobas or 200 pounds apiece; they will transport as much as that 100 feet up the stone stairways of the old mines. At the Prospero mine, each man carries four tons per shift a vertical height of 75 feet, and a length of 400 feet, at a cost of 50 centavos. At Guanajuato I saw some excavating for foundations done at 25 centavos per cubic metre, the rock being carried a distance of 200 feet across the gravel of a barranca. They are good blacksmiths. At the Peregrina the native workmen took out the flues from a boiler that was in bad repair; they cut the tubes at both ends, and welded on an extra piece to make the original length. One smith and three helpers welded 24 tubes in 12 hours. The native blacksmiths are good drill- sharpeners, though better at shaping than at tem- pering. Here is the place to tell the story of a strike that occurred near Guanajuato. Order is not difficult to maintain in a mining town like Guanajuato, because the people possess a lively respect for the representa- tives of the law. The strike at the Peregrina mine affords an example. In that episode there figured 500 peones; there came four undersized soldiers and a most unimpressive jefe politico. The paiio was full of the striking miners, ready for a riot. The little jefe WB^stsaest)^^^m ■ ■,it M !f I li N \ * if ! io6 AMONG THE MINES OF MEXICO told the manager to open the patio; the big doors swung aside; the four soldiers entered with their muskets clubbed and the jcfe behind them with a drawn sword. The laborers scattered like rabbits, the four soldiers whacked all within their reach, the peoncs fled and fell over the dump; the strike was over! The authorities keep a close grip on the native population. Strikes are rare. They occur occasion- ally in the cyanide plant, where the men who tram the sand are inclined to think that they do too much. El Hro has never had a big strike. Should there be any disorder or insubordination requiring serious action, the jefe politko (sheriff) is asked to call out his ruralcs (police) and these arrange affairs by capturing the ringleaders, after which the crowd scatters at once. The peon is an inveterate thief, the mill-hands steal ore and the precipitate in the zinc-room when- t'ver possible. When caught in the act, the culprit s turned over to the jefe politico and in short order the latter sentences him to serve in the army. He is made a compulsory soldier and may be drafted to the hot country of the Yucatan peninsula, which is equivalent to exile, 'i o put the peon in prison means nothing to him; he has a quiet time, his friends bring him food, he is required to clean the streets or do similar municipal work; it is no punishment to him; but to be placed in the army means wailing and the gnashing of teeth among his friends. (ri)af Ur 16 PACHUCA — AN OLD MINING CENTRE — ANCIENT METHODS — THE DISCOVERY OF THE PATIO PROCESS — REVOLUTIONARY DAYS — THE INVA- SION OF THE MODERNS. ACHUCA is approached from V? Mexico City over a railroad that traverses the wide volcanic plains covered with vast planta- tions of maguey, in serried lines stretching out like an army in skirmishing order. A journey 3 of 62 miles brings the traveler to he foot of brown hilis that rise to above the valley, v •'•'i is 8,200 • cn-level. The morning I ~...v. em first, st.ii liid their summits .''id ?'!> them the 1 rr'a*;' J, is like far- a whitt u a range i feet abo- : the mists possibility of a greater height, away Kalgoorlie in the matter of dust ; it swirls round every street corner and smothers the picturesque in the dry folds of the commonplace. In the plaza, among the graceful pepper trees, there are two speci- mens of eucalyptus, fifteen to twenty years old, whose dark blue foliage and ragged columns told of a land unknown to the civilized world for 250 years after the Spaniard invaded Mexico. The antiseptic odor no AMONG THE MINES OF MEXICO I I J I \h i H : ■1 ! I * i 1M.:I f of these gum trees recalled to me many a glorious day spent in the Australian Alps." The pepper trees that ornament Pachuca also came from a far country; they are called the Peruvian tree, having been introduced by one of the last of the Spanish viceroys, who brought them from Peru, where he had previously held office. The eucalyptus was introduced thirty years ago by the minister de fomento, but it has not done very well, the soil being too dry. In every respect, save its dust, Pachuca differs from any modern mining town in English-speaking countries. The corrugated shanties and the white tents of ephemeral mining camps are here replaced by a solidity of construction that bespeaks a hereditary oc- cupation. Massive stone buildings overlook the nar- row cobble-paved streets and some of them have architectural pretensions, as for example the offices of the Real del Monte Mining Company, an enter- prise of historic continuity and associated with names famous in mining, for John Taylor & Sons were en- gineers of the old company sixty years ago. Even to this day John Taylor's name is honored, and in the Santa Brigida mine there is a level that continues to be called the canon dc Taylor. Another reminder of the Cornish invasion is seen in the fine stone man- sion, half smothered in beautiful bougainvillea, of " For even in Austr.ilia there is mountaineering and snow. Go to Bright and Harrietville in Victoria during August and climb Feather Top or Mt. Bogong. Experto credite. u. o f \^ I I I l^ni m IH 4lr. f ANCIENT METHODS OF SMELTING III Mr. Francis Rule, whom his countrymen called Capt. Frank Rule, and the Mexican?, Don Pancho, an honored and successful mining engineer. Pachuca has a population of 40,000, and of this number 7,000 work underground. The district pro- duces 6,000,000 ounces of silver per annum and 30,000 ounces of gokl representing 9,000.000 pesos or $4,500,000. Most of the lodes that are productive today were discovered by the conqutstadorcs and their immediate (Spanish) successors, aided, to .some extent, by the natives (Aztecs). The Spanish pioneers sought for gold placers and extracted the metal— not much — tiiat they found, by washing, supplemented sometimes by amalgamation. What silver ore they encoun- tered, they smelted with carbonate of soda (the tcqucsquitc of the Spaniard and the earlier tequixquitl of the Aztec), a supply of which came from the la- goons in the valley — for instance, in the lake of Tezcoco. Their fuel was charcoal made from fir and oak; poisibly also thoy used some lead oie to collect the silver in their rudimentary smelting operation. When llartholome de Medina invented the Patio process at the Hacienda Purisima Grande he revolu- tionized the silver mining industry. This was in 1557; up to that time o.ily the richest mineral could be smelted and there was no process for treating the low- grade ore. Medina was the first to apply amalgama- tion to silver, despite its much earlier application in gold mining. This was a basic improvement, but he ^1 I iJ 112 AMONG THE MINES OF MEXICO also elaborated the f ''^r treating silver sul- phides by chloridizi t in the presence of copper sulphate, usiw^ .o mix the charge. This is the Patio process, so caned because it takes place in an inner court or yard (the patio) and from Medina's day to this, for 350 years, it has been the characteristic feature of Mexican metallurgy. In 1739 Pedro Jose Romero de Terreros, who had made money by mining in Queretaro, visited Pachuca and became impressed with the Real del Monte dis- trict. He spent his capital, said to have been $60,000, and borrowed more to carry out his explorations, but finally he struck a bonan2a and won a big fortune. He gave the king of Spain a battlesliip and other large gifts; in consequence, he was ennobled. As Count of Regla he became the founder of a family of successful miners. The}' worked the mines until 1819, when the disorderly condition of the country, due to the revo- lution against the Spanish Government, caused opera- tions to cease. A few years later the mines were sold to an English company, which look charge in 1824. The doings of that company are still mentioned in every Mexican guide-book, the writers of which dwell with gusto on their wild speculation in London and their reckless extravagance in Mexico. The £100 shares rose to £16,000 apiece, almost before a start had been made; enormous sums were spent at the mines, no less than 1,500 tons of machinery being hauled across the country from Vera Cruz. In 1848 the company went into liquidation, after extracting THE DAYS OF THE REVOLUTION "3 $16,000,000 in silver and spending $20,000,000. In 1850 a Mexican company was organized, and it is this o ' rsliip that survives without important cliange to the present day." The first manager of the Mexican company was the Inst manager of its English prede- cessor; that was John Buchan, obviously a Scotch- man; and despite the change of ownership there v^as a continuity of management, the Spanish and the British members of the staff co-operating loyally. During the Maximilian days and the later successtve fights for the presidency, the mines at Pachuca si^- fered from the depredations of the military, partly soldiers but mostly bandits. Stories are told of the miners having to live underground for days at a time and of the money hat was buried in the U-vels when people at surface were bemg robbed without compunction. Up to 1890 it was necessary to carry a revolvc-r in the streets of Pachuc?, even in the day- time. The Real del Monte office, for example, is a massive .stone structure which originally did duty as a fortress; the rotmd towers, slotted fot rifle-fire against attacking forces, still stand a ■ each of the four lorners of the buiMing. Every mine even today is enclosed by massive walls, which at one time served as protection from assault, although nowadays they ;ire retained for a different reason. They safeguard t!ie dumps, which are recognized as having a possible "Since thi- ua^ written the Real del .Monte mines have been sold to a Button corporation The Anglo-Celtic invasion has begun! I .1 .l! I,] 1^1 f it 114 AMONG THE MINES OF MEXICO f 111 value in the future, for the pcones are born thieves and their pilfering is a constant nuisance to the mining companies. For this reason also the reduction works, or haciendas, are enclosed within lofty walls, which are entered by arched doorways, guarded by a watchman. At noon the women crowd at these entrance gates with baskets containing the dinner of their men, who meet them there; they often squat down beside the wall to have a chat and share a smoke, until the lengthening shadow marks the time to resume labor. All the peon employees of the mines and mills are rigorously searched by the velador as they pass out through the gate of the enclosure. The ordinary peon laborers are cheap enough, but it is what they steal that makes them costly. They are inveterate thieves. All sorts of precautions are taken. At the Hacienda Loreto, the manager proposes to make his men pass through a water-tank and compel them to shout "Viva Mexico" three times in order to detect any amalgam that they may have in their mouths. And they have other schemes for overcoming their excessive poverty otherwise than by earning scanty wages. For in- stance, there is a great deal of mutilated coinage and also of counterfeits. When pay-day arrives, the work- man, in sweeping his silver across the office-counter, will try to palm off a spurious coin by claiming that the cashier gave it to him. The trick is detected by the warmth of the coin, which the man has held in his hand just before passing it in. Punishment for ^.M A MACHINE-MADE TORTILLA "5 this trick is severe, as it is an offence against the Fed- eral Government; culprits are apt to get a sentence of several years in jail. At Pachuca the application of mechan'^-l inven- tion to a basic industry is amusingly illustrated by the fact that even tortillas — the common pancake of the country—are made by machinery. The people of Pachuca patronize the establishment where this is done because the cost of the machine-made tortilla is one half that of the hand-made article and it is equally palatable. The excellence of the local tortilla may ex- plain the vigor of the native miner; for the barateros of Pachuca are recognized to be the best miners in Mexico; they have learned from the Cornish, who settled in the district more than fifty years ago and intermarried with the natives. The Guanajuatenses, or men from Gunanajuato, have the reputation of be- ing quarrelsome and less efficient as miners— which may be for lack of admixture .uh a strain of Cousin Jack, but we do not n • the suggestion with any confidence. The natives of this district, like most Mexicans, are wonderfully clever in estimating the silver con- tent of an ore with which they are familiar; stolen ore is invariably bought by valuation at sight. Even the tributers (those that work on tribute or partido) sell the product of their work to the proprietary com- pany on the basis of an estimate of its assay-value made at sight by an official termed the rescatador; if l/< ii6 AMONG THE MINES OF MEXICO the appraisal is not satisfactory, they can sell their ore elsewhere. Tributers get an eighth of the stuff they mine — that is, one sack in every eight — the remain- der going to the company. This is the system at the Real del Monte mines; other companies work chiefly on contract. A. (Tl^apUr \7 REAL DEL MONTE — OLD MACHINERY — THE VISCAINA LODE— ITS EARLY ROMANCE — LA DIFFICULTAD — AN ELECTRICAL PUMP — LODE STRUCTURE — LOCAL GEOLOGY — SCENERY. E, that is Robert M. Raymond of El Oro and the writer, made an interesting visit from Pachuca to the neighboring mining town of Real del Monte; this courtesy, and much infor- mation, we owed to Sefior Don Carlos de Landero, the man- aging director and one of the most accomplished of Mexican mining engineers. In a large carriage drawn by four mules, with a driver and footman dressed in the picturesque uniform of the company, to the crackling of the whip and the heavy rumbling of the wagon over the cobblestones of Pachuca, we started on the morning of October 30, before the misis had uncovered the crests of the range where lies the treasure unexhausted despite the mining of three and a half centuries. Emerging from the nar- row streets, the road cuts the edge of the valley and winds slowly among the brown hills, dotted with wild maguey. At the San Francisco shaft of the Santa Certrudis company we saw a large pumping engine Ii8 AMONG THE MIXES OF MEXICO I 1?!. I w of the Cornish ;ype, built by Bickle & Co., of Plymouth, in 1S98. The cylinder is upright and 90 inches in diameter; the stroke is 9 feet and the pump- column 18 inches. The capacity is S'/t cubic metres or 1,000 gallons per minute, from a depth of 400 metres. This pump was chosen by Capt. Frank Rule, under a former administration; it was obtained at an enormous cost, on account of the difficulties of trans- port and erection. Although made in 1898, it was not at work until 1902. But once erected, the pump has proved most efficient. The boilers are single- flue, with two fire-places and nine Galloway tubes, so as to be well adapted to the use of mine-water. The distance from Pachuca to Real del Monte is six to eight miles, by the various roads. Haulage of ore costs three pesos per ton, the road crossing the summit of the range, 1,100 feet above Pachuca. Only one trip per day is made. Nearing the divide, the road crosses the red out- crop of the Vizcaina lode, famous in local mining annals as that which gave such wealth to the first Count of Regla. The story is worthy of repetition, although it has several versions, the most reasonable of which is here offered. In 1739, Pedro Terreros, who is said to have made $60,000 in the mines of Queretaro, happened to visit Pachuca. He was an experienced miner. Becoming interested, he aban- doned the journey to Spain, and started mining at Real del Monte. Humboldt speaks of "the vein of la Biscaina or Real del Monte;" it is now spelt \''iz- 3 Ji f^ mt H MICROCOPY RESOIUTION TEST CHART ANSI and ISO lESI CHART No 2 1.0 I.I ;-iM Ilia It u^ t li£ lii 2:0 1.8 1.25 II 1.4 1.6 _^ APPLIED IM/IGE Jnc ^^ 'tib; tail Uj,r. r-l'tft T' ^ i I C '^'Iv.: P\m : I !!! '} 3 i THE VISCAINA VEIN 119 caina (pronunciation remaining unaltered, but the Mexican orthography being substituted) and it is evident that the name was given after Terreros came there, for it refers to the country of his nativity, Biscay. Most sea-goers know the Bay of Biscay. Terreros was successful, but the increased flow of water compelled him to abandon the main Santa Brigida workings when they were 120 metres deep. In the early part of the eighteenth century the water in mines was hoisted by methods that still survive, namely, hide bags and a windlass. Even in Hum- boldt's day, sixty years later, much the same practice obtained. He says: "A bag full of water suspended to the drum of a barritel with eight horses {malacate doble or double horse-whims) weighs 1,250 pounds; it is made of two hides sewn together. The malacate doble has four arms, the extremity of each arm has a shaft {timon) to w1 ch two horses are yoked. The diameter of the circle traveled by the horses is seventeen varas and a half (that is, 47^/^ ft.); the diameter of the drum is twelve (32 ft.). The horses are changed every four hours." However, the influx of water was finally over- come in miner-like fashion by driving a drainage adit (jof(2^o«) into the hillside. Humboldt says: "Avery enterprising individual, Don Joseph Alexander Bustamente, was courageous enough to undertake a level near Moran ; but he died before completing this great work, which is 2,352 metres in length from its mouth to the point where it crosses the Biscaina '■^^^M'^. lao AMONG THE MINES OF MEXICO 1. ^\k^. .'i *■ '^HH ', % t 1 1 vein. * * * The level was only finished in 1762 by Don Pedro Terreros, the partner of Bustamente. ♦ * * The level of Moran traverses the Biscaina vein in the pit of San Ramon at a depth of 210 metres." But these worthy miners were plain 'Jose' and 'Pedro' until long afterward, when their wealth and public spirit led to their ennoblement. This adit of over a mile long was started in 1850 and was finished in twelve years ; the smaller veins inter- sected during the progress of the work furnished funds for the continuation of the adit, but before it was completed the projectors of the enterprise were — as is usual in mining romance — down to their last penny. When the vein was cut below the Santa Brigida shaft, the adit was in bonanza. This was at 210 metres below surface. The orebody was worked for twelve years and the money secured by Terreros enabled him not only to equip the old mine but to buy large plantations in the vicinity. He became enor- mously wealthy; "this muleteer and illiterate shop- keeper," so says the chronicle, became Count of Regla. When his children were baptized the proces- sion walked on bars of silver. Furthermore, he loaned money to his sovereign — this was one of the privileges of rich men in those days ; nowadays they buy yachts and found trust companies. Humboldt says that Terreros "known by the title of Count of Rc'a, as one of the richest men of his age, had in 1774 already drawn a net profit of more than 25 mil- lions of livres turnois ($5,208,750) from the Biscaina '-\ DE-FORESTATION 121 mine. Besides the two ships of war that he presented to King Charles the Third, one of them of 120 guns, he lent five millions of francs ($1,041,750) to the court of Madrid, which has never yet been repaid him." Near the summit of the ridge, at Hiloche, where the Pachuca road descends to Real del Monte, there is a fine grove of primeval oak, suggesting the forests that covered the plains and hills of Mexico before the Spanish conquest. A good purpose is shown in the young plantation of cedar and eucalyptus that has been started in this locality. Mexico has suffered enormously from de-forestation, and the laying out of trees ought to be one of the first duties of the Fed- eral State authorities, as well as of public-spirited citizens. At Hiloche is the big pavilion built in 1901 for the entertainment of 600 people, constituting a party of the American Institute of Mining Engineers. That occasion is remembered by a great many who are now scattered over the mineral regions of North America. The pavilion has not been demolished; it is used for picnics. Descending by a winding wagon-road we soon reached La Difficultad, at an altitude of 2,793.27 metres. This mine is one of the chief openings of the Real del Monte company. It affords, among other things, an interesting example of pumping practice. In the shaft-house there is an enormous engine of the marine type built by Richard Hart- mann, of Chemnitz (Austria) in 1889. This operates Jii k f! laa AMONG THE MINES OF MEXICO two stationary Rittinger pumps, with a discharge of 890 milHmetres and a stroke of 2.5 metres; also a sinking pump of the same kind with 850-mm. discharge and 3-m. stroke. The capstan engine, for handling heavy piei s of pump and facilitating repairs, is from Tangye Bros., of Birmingham (Eng- land). These pumps have been replaced recently by a new Swiss pump, but they are kept ready in case of need. The Swiss pump comes from Sulzer Bros., at Winterthur; it has a capacity of 8,400 litres per minute to a heigh of 240 metres, delivering the water from the bottom, at 540 1 1., to a drainage level at 300 m. below surface. The pump was installed on July 23, 1905; it has four compartments, alongside, the water being forced from one into the next, each pump re-enfo :ing the other. It is operated by a 650-h.p. motor working with 380 h.p. and was taking about 4,000 litres at the time of our visit. The motor of this rotary pump was supplied by Brown Boveri & Co., of Baden, and is of the three-phase induction type. It is constructed to yield 650 h.p. at 60 cycles or 900 rev. per min., using 160 amperes at 1,100 volts. The pump-shaft is coupled direct to the motor-shaft. The motor was running at only two-thirds its normal speed, yet it was heating rather badly; this is charac- teristic of most Swiss motors. Although Swiss and German motors are cheaper, they have got no stamina and will not stand an overload like the Ameri- can-made machines, some of which are actually guar- anteed to carry an overload of 25 per cent for two itii i s < < a O z < ' i i V. t ' . 1 ' ■.< ' I 1 !tr ^ 9C O i — -r. U 3 5 .h ii in r* in 1 *i T A BIG PUMP "3 hours or even longer. No suction is used, the pump draws from a dam that affords a 50-ft. head. The pressure in the column is 25 kilograms per centimetre. The sump under the rotary pump is three metres deep, the water from it being raised to the dam by a Knowles pump geared to a motor, which gets its im- pulse from a Koerting elevator, operated by a stream of water descending from the 300-m. level. These Swiss centrifugal pumps are used in other mines at Pachuca and they are said to be highly satisfactory; they have a particular and effective arrangement of the runners; the makers of them are willing to guar- antee a specific efficiency, which, as yet, American manufacturers will not do. Four of these Sulzer pumps (each of 1,500-gal. capacity) have been or- dered for the El Oro mill, to raise the return water and solution from below the zinc-room. At the pump- station there was the usual shrine with lighted candle on each side, and ornamented with artificial white flowers. Here we had a timely luncheon and a pleas- ant talk with the engineers of the mine. The first 50 ft. of the shaft is lined with masonry • orted by arches sprung from the country rock. i!? shaft is not continuous; from the 440-m. level there is a counter-shaft to the bottom. This is de- scended on a cage with steel-rope guides. At the 440-m. level there are some large underhand stopes; when the flat cable is worn out, its separate strands are used for hoisting ore underground, in hides that hold 25 kilograms apiece. These are not made in the 1 1 I, Il 124 AMONG THE MINES OF MEXICO shape of buckets, but they are laid flat, the broken ore is put on them and then they are laced so as to make a parcel. The ore hoisted by windlass in this way is discharged into side-dumping cars, which are run on a wooden track lined wiih an iron band to the sta- tion at the shaft, where the ore is dumped onto a plat- form to be shoveled into a skip. Altogether, it affords a curious mixture of old and new methods; it is a hybrid practice. At the 463-m station we changed from the counter-shaft to the main shaft, and while waiting for the cage we watched some men who were loading the accumulated waste into ox-hides; these held 300 kilograms or the third of a ton, and after being laced they were hung by chain to the bottom of the cage, the material being used at the next level for filling. All the rock broken in shaft-sinking is raised in this way. and even water, just as they did in the days of Pedro Terreros. As the five men filled and then laced the rawhide, they put it aside lor the next trip of the cage; when I first saW it, I thought it was the carcass of a dead mule, and it smelt like one. In walking llirough the workings, one notices that the cross-cuts are walled up, the walls being often sealed with clay to divert the ventilation. There is a good deal of masonry in the mine, and different parts of it are shut off by iron gates, so as to prevent pilfering. There is no timbering worth mention. The ore is mainly quartz; it is often ribboned by the banding of rhodonite and sulphides (iron pyrite and argentite) ; in many respects it reminded me of the -PI* w THE SANTA INEZ VEIN las veins in the Alice and Lexington mines, at Butte. Montana. The accompanying sketch (Fif;. 17) of the Santa Inez vein is i fair example of the lodes in the Difficultad mine. Both walls are well defined; on the fool (G) there is a wet slip; £ is a band of rhodonite; L) is mainly amethystine quartz; F and B B are sul- phide streaks; J B is massive poor quartz; B to C is mottled by brecciation; between D and E there are Fic. 17. Streaks and spots of sulphides, including argentite, a little galena, and occasional yellow zinc-blende; E F is brecciated andesite, now partially silicified; F G is crushed quartz. The whole widtl of lode is seven to eight feet. At the Difficultad mine, the low-grade ore left on the dump is said to contain 400 grams >f silver and 2 grams of gold. This aflfords an idea of the cost of working. At the Barron mine, the ore 1 ^i:! I "ill '::t if i' I' I 1 'i li 136 AMONG THE MIXES OF MEXICO is said to average 800 gm. silver and 4 gm. gold, while in the Difficultad it is said tc» carry, for an average of eight metres, not less than 1 kilogram of silver and the usual proportion of gold. It may be added that the prevailing formation about Pachuca is andesite ; the veins arc lines of frac- ture which have been healed by silicification. There exist in the district several islands or caps of basalt connected with vents and there are dikes of rhyolite accompanied by slight mineralization along their walls. For details of the geology, the reader is re- ferred to a valuable paper by Senor Ezequiel Ordonez." On leaving Real del Monte by the southern road a good view of the surrounding country is obtained by looking back. To the left is a rounded ridge clothed with groves of oak; to the right, a conical hill surmounted by a coppice of dark oak and cedars of Lebanon, and under their ohade the white-walled English cemetery where many a Cornishman has gone underground for the last time. Between these flanking hillslopes, framing a picture, there are the white houses and red roofs of the town, surmounted by Moorish church-towers, among which, curiously out of place, is the Cornish engine-house with its lofty chimney rising above the castellated enclosure of ti.e Difificultad mine. Behind the town are green hill- sides, and further back, after the interval that marks "'The Alining District of Pachuca, Mexico,' Transactions American Institute of Mining Engineers, Vol. XXXII, pp. 224-241. ■In A WIDE PROSPECT IJ7 a deep barranca or gorge, there stands, outlined against the hlue sky, the mountain crowned by the battlemcuted rocks of Zumate. After crossing the summit and beginning the long descent to Pachuca, there is much to be seen that typifies the Mexico of today. The liroaf nd winding road cuts through gray-purple andesi ■ it is lined with massive stone culverts and doet redit to the engineers responsible for the construrtion. ft skirts brown hillsides, darkened in spots by the wild maguey, with the tall central stem that is the sign of an uncul- tivated condition, i ;ere is an occasional cactus and a few palms, mainly the izote from the fibre of which are made the straw hats of the peones. Whitewashed monuments dot the surface and, in their occasional sequence of direction, mark the boundaries of mining property. Yellow scrub fringes the road and en- hances the value of the purple in the distance. A flock of sheep, a string of patient donkeys laden with charcoal from the forests, other burros coming irom the valley and laden with pigskin bags inflat' 1 with their burden of pulque; some saa-faced Indian men trudging up hill, one of them with a baby slun^ . i her rcboso, another walking patiently v.'hilr her man rides alongside on his mule; then a cava!^'"r with wide sombrero and gaily caparison^ ' idille, a .irrape thrown over the silver-mounted pumiii.i and riding his horse superbly; a wagon heavily laden with sacks of ore, its brakes crunching noisily, drawn by ten mules, with silver bells, and driven by a brigand-like muleteer; all 138 AMONG THE MINES OF MEXICO these are part of the stream of Hfe that we pass or meet on this road. But the foreground is not all the picture; at our feet, to the south and west, lies out- spread the vast plain known as the valley of Mexico, crossed by white streaks of dusty road, checkered by squares of cultivation, the yellow patches of maizf?, the green of barley, and the occasional darker shade of alfalfa, with other rectangular lines tl t mark the serried rows of macjuey?'' Sunlight and shadow shift over Ibe vast expanse; in the distance, more than 16,000 feet high, rises the snowy crest of Ixtaccihuatl — 'the white woman' — partially veiled in a cloud, and by the Aztec name recalling the pathetic fate of an ancient race. In middle distance there is a blue ridge behind which is jNIexico City, and to the right, under the mountain of San Cristobal, hides the dusty town of Pachuca; in front are several famous mines — Cortcza, El Lobo, Santa Gertrudis, Barron, and La Blanca — each in its walled enclosure and dominated by a towering shaft-house of stone. And then, before we realize it, we are awakening the echoes of the nar- row streets of Pachuca, and amid the cracking of our cochcro's whip and the warning shouts of those that clear the way, we pull up at the railway station, just in time to catch the train. "There is no maguey on the west coast of Mexico: only one-tenth of the population of the entire country drinks pulque, chiefly in Mexico City and its vicinitv, including such mining towns as Pachuca and El Ore. It if unwholesome because it is drunk when still in process of fermentation; if the people d d not take this stimulant they would take some other. |;? Cbap Ur IS THE REDUCTION WORKS OF PACHUCA — THE HACIENDA DE GUADALUPE — TREATMENT ON THE PATIO — A METALLURGICAL SURVIVAL — SOME CRITICISMS. ACHUCA is proud of its hacier. das de beneficio or reduction works, of which there are seven large ones. Six of these are in operation and they treat 5,000 tons per week. Three of them are custom works; those of Guadalupe, La Luz, and Loreto are not. At the entrance of the haciendas, and even of private residences, one sees the big iron hoods of the mercury retorts. They are buried in the ground, one on each side of the gateway and, being 5 to 5^ feet long, they have the appearance of spikea guns. The Hacienda de Guadalupe treats 900 tons per week, this being the output of the Santa Gertrudis and Guadalupe mines. At the mine the ore is broken by hand, and picked over; the 'best selected' assays "ver 10 kilograms of silver per metric ton and is sent to K .rope, the second class, carrying less than 10 kilo- grams, but over 2 kg. per ton, is shipped to the smelter at Monterrey, while the mine-run, containing less than 2 kg., comes to the hacienda. Here it is screened to ^ I !) I; I , I !l 'ty I I li 130 AMONG THE MINES OF MEXICO inch, the oversize passing through Cornish rolls, while the undersize is shoveled into bins. These are built of stone; they are brick-lined at the opening, whence the ore falls into cars that take it to Chilean mills. The oversize, after passing through the rolls, goes through a trommel (2 ft. diam. and 3 ft. long) with half-inch openings, the oversize going back to the rolls while the undersize falls to the ground, to be shoveled into cars, in which it is taken to bins above the Chilean mills and subsequently fed into them by shovel. There are 14 Chilean mills; the die-rings (5 ft. inner diam., 6 ft. outer) and shells are composed of Siemens & Martin steel, made in Germany. The die lasts one year, the shells twice as long. There is an iron ring inside the steel shell. Each mill (inside diam. 1.85 m.) has six openings, guarded by a 60- mesh screen, all on one side. The discharge passes into a vat, whence it is raised by a centrifugal pump to distributors above the 14 concentrators. These are vanners — with belt 1.8 metres wide — known as the Johnston table and manufactured by the Risdon Iron Works, San Francisco. It does good work, the belt being heavy, so as to give it the motion of a batea instead of being simply supported on a frame. The concentrate is shipped to Europe; it contains 14 to 15 kg. silver and 100 gm. gold per ton. The yield (from 900 tons of crude ore) is 21 tons per week, of which 13>4 tons come from the vanners and 7^ h from canvas tables that receive the tailing from the vanners. k THE HACIENDA DE GUADALUPE 131 The tailing that results from this concentratiori process goes to vats or bins; these are structures built of masonry, 4 to 5>^ meties deep. Here the pulp settles and the water is drawn off to a well, from which it is pumped for use in the mill. Stated briefly, the process of ore reduction consists in grinding fine with Chilean mills, extracting the heavy sulphides (with their associated gold) on concentrators, and then treating the tailing (containing the bulk of the silver) by amalgamation on the patio. On the flat ground below the terraced slope form- ing the site of the mill just described, there stretches the broad expanse of the patio, where the process of that name is carried out. Patio means a yard or enclo- sure, and the process derives its name therefrom. The patio of the Hacienda de Guadalupe is the size of a city square, it is paved with stone and divided into rect- angular spaces, 30 by 25 metres, in which twenty sep- arate charges or tortas, each weighing 300 tons, are undergoing various stages of treatment. Each bin or vat that holds the pulp or tailing from the concen- trators, has a vertical opening 5>4 feet wide which is kept closed by a series of boards (6 to 9 in.). These are removed one by one so as to allow the sludge to flow along the canals— 3 ft. high, 6 ft. wide and built of stone — that lead into the patio itself. The flow of the sludge is assisted by a scraper (camon) pulled by a horse. This scraper is a plain plank, two inches thick, to which chains, connecting with the traces, are at- tached, as shown in the photograph facing page 134. m y \ \\Jih ... :|/ 132 AMONG THE MINES OF MEXICO El camonero, the horse that does this duty, must be strong, for the work is hard; he scoops the slime along, to the accompaniment of much splashing and the encouraging shouts of the driver who controls the operation. Openings, at various points along the canal, serve to distribute the slime to separate rectan- gular stone-paved spaces, where the chemical work is done. Each rectangle, 25 by 30 metres, is del'mited by two timbers (4>4 by 8 in.) placed one over the other so as to make a partition 16 inches high. The torta that they enclose is 30 centimetres thick. The slime or tama is allowed to thicken, by loss of moisture through evaporation. Then comes the ad- dition of the first chemical, common salt, which is thrown over the charge like a shower of hail. The salt is obtained from the lagoons near Zacatecas and is adde . in the proportion of 6 to 7 per cent of the weight of the ore. This is an excess, but it is found to accelerate action and to diminish the consumption of mercury. After this part of the process (called ensalmorar) is finished, the mixing or repaso begins. This is done by the trampling of horses or mules. One man, himself on horseback, drives 12 animals, four in a row, tied by the neck to each other. The cracking of the whip, the slushy tramp of the horses, and the shouts of the driver give animation to the scene. This goes on by day only, from 7 in the morning until 2 o'clock in the afternoon. When the day's labor is ended, the horses are driven through a big tank to be cleansed, when more shouting and splashing enlivens THE PATIO PROCESS 133 the hacienda. This mixing continues for 24 to 30 days. Each afternoon every portion of the torta is turned over with shovels in the hands of 12 to 15 men. After the first three days comes thr addition of copper sulphate (bluestcne) followed by further, mixing, and then the mercur;- is introduced. The 'bluestone' comes from the Unitod States; it is added to the torta in the proportion of 0.4 to 0.6 per cent of the weight of the ore. In looking over a patio in which the charges are in various stages of treatment, some just salted, others just showered with copper sulphate, the contrast between the rectangular patches of white and blue leaves a vi/id impression. The mercury is added in the ratio of fully eight times the amount of silver estimated to be in the charge undergoing treatment. It is carried in a cloth, folded like a ':ag, and swung freely, so that the mer- cury squeezes through in the form of small globules. This is done to ensure thorough assimilation; the operation being appropriately termed incorporacion. Five or six men perform this work, on the fourth day. At the end of the process (after 24 to 30 days, as de- termined by test) more mercury is added, in the pro- portion of 5 kilograms of mercury for each kilogram of silver present in the charge, makinf' about 2,500 kg. to each torta, this being introduced for the purpose of collecting the amalgam already formed. This operation is termed the bafio. During the continu- ance of the treatment the torta is tested by panning ( i i ',• ■■ r ! ii .■■> j.: 134 AMONG THE MINES OF MEXICO samples in clay saucers (6 in. diam.) called jarros. The operator pans the stuff down to a button of er- cury and squeezes it between the thumb and index finger, to test its consistence, a flat bit of amalgam remaining, of a size indicating the extent to which amalgamation has proceeded. The rejected sand from this .anning undergoes the ordinary fire-assay; when there is no further decrease in the content of the tailing, complete extraction is indicated and mixing on the patio ceases. Then the horse with the scraper (camon) is em- ployed to move the charge forward to a sump or lavadero, the patio being finally swept clean by 12 to 16 peones with brooms; the mercury can be seen in small pools and is splashed about during the manipu- lation required for this clean-up. The charge is moved to a basin {cajon), 8 by 10 ft., where seven men, standing in water just ove- their knees, stamp around, and stir the stuff, while clean water is being added and fresh material is being fed into the cajon. The top of this basin is level with the floor of the patio; the bottom of it is six feet below the pavement and is enclosed in masonry, except on the lower or outlet side, where there is a barrier made of two boards, which are perforated with 3-inch holes, twelve of them, in cK:sters of six each. The amalgam and mercury col- lect at the bottom, while the overflow drops into large cast-iron hemispherical basins (apuros), of 2>4 ft. diam., which serve as traps. There are five of these, \ . ICi- Camiinkho MoVIM; Sl.lMK (INTO THF Patio ■\ Tube - Mill IN THE Hacienda 1,\ Union AT Pal H CCA ' t m v^m . :vl'"f ^ trim \ Pi f <;. MK.HANIC.M. ri.ii(;H. II. llnksKs MiMM;. K Mkn Siii.vki.im; Two ViKWS OF THK P.\TIO PROCESS ■J ' i COLLECTING THE AMALGAM 135 distributed along the exit-sluice below the sump. From the last apuro, the pulp flows over two parallel sluices with riffles, and in this a dozen or more boys, 8 to 9 years old, stamp around, in order to aid the separation and arrest of any escaping amalgam. These little fellows, chocolate colored, with big straw hats and thin bare legs, are kept on the move, so as to stir the slime; they wade around at the bottom of a canal 10 to 12 feet below the lev^l of the patio. They receive 37 centavos, or about 20 < ents, per day. Most of the amalgam is caught in the sump and in the first two apuros at the head of the sluices. This clean-up occupies 16 to 17 hours. Finally, the rich deposit at the bottom of the basin is washed, one of the boards of the lower barrier being removed, while fresh water is turned in. What amalgam gets out of the ca)on, lodges in the first (and biggest) apuro. At the very end of the operation more water is added; the peones use scrub-brooms and sweep the bottom clean. The amalgam and mercury make a big show- ing; they are lifted in iron ladles; these are made from the flasks in which the quicksilver is bought, their tops being cut off, and an iron handle 'nserted. From 1,500 to 2,000 kilograms of amalgam are obtained from the clean-up of a single torta. Six hundred horses are used on the patio; they last four or five years, if young; the older ones last only six months. They become poisoned by the copper sulphate; hence the washing each day. Some %m^ 1 .-a|,, 136 AMONG THE MINES OF MEXICO of the horses are found to gather a lump of amalgam in their stomachs, as much as half a kilogram, say, one pound. This used to be removed when the horse died, but now the Government claims the deceased animal, without permitting dissection, and it goes to the crematory. What happens to the silver amalgam is not stated. ,., ^ The extraction is 80 to 85%, the tailmg (jales) containing 100 to 150 gm. silver, say, 3 to 5 oz. per ton. The gold is caught in the concentrate on the vanners; practically none of it is saved on the patio. Never- theless, down the creek there are two plants that re-work the tailing from the hacienda. To anyone accustomed to stamp-milling, it is surprising how the mercury is splashed about. The pavement of the patio itself must absorb some of it, for this pavement is made of slabs, which are irregular in size, but usually 1 by 1>^ feet, of volcanic stone, a basalt called recinto. In another part of the hacienda one can observe the working of a mechanical mixing machine, de- signed to be a . oor-saving modification of the Patio process itself. In a rectangle, 20 metres wide and 75 meties long, a plough, with eight blades, movmg sideways, travels up and down. It is operated through a ratchet gear by a man who sits on the machine, as it is pulled by an endless cable of one-half inch diameter. This treatment requires 45 days and gives the same extraction as the ordinary Patio A MECHANICAL MIXER i37 process. The superintendent prefers the old-fashioned horse method because it requires less time. It can be said truly that the trampling of the animals affords a better aeration of the charj:je than the mechanical plough, which appears to go through the sludge rather than turn it over. There should be more turning of the furrow. Mechanical devices in place of animals were tried long ago and they have been used in different parts of Mexico, especially Sonora. In M. C. Roswag's 'Metallurgie de I'Argent,' there are descriptions of such substitutes, which in English are called 'knead- ing' machines and in Spanish repasadoras. Other observations are permissible. The small boys that tramp about in the tail-sluice give their toes as riffles to assist the settling of escaping particle? of amalgam. The stirring in the clean-up basin, as done by seven grown men, has its humorous feature, but it is effective. The method of moving slime onto the patio by the camonero is an absurdity at first sight, but it obviates a costly conveyor, and botn horses and men are cheap at Pachuca. The Chilean mill affords better grinding than the pounding action of the stamp, although it seems strange to see the pcjncs shoveling into the mills and then taking a rest, when a mechanical feeder would do it so nicely. Th*; tern porary canals made between the torta and the cajon, to confine the passage of the pulp, are kept tight with manure, the droppmgs of the animals on the patio, I ' 138 AMONG THE MINES OF MEXICO thus contributing smells to the sights, a combination not uncommon in Mexico. There is a striking con- trast between the modern vanning tables and the patio itself, the whole picture exhibiting a sublime disregard of all modern mechanical ingenuity as applied to the handling of material. The accompanying photographs will aid the foregoing description. J A indicate the position of the Johnston vanners; B B are the sludge vats, with their outlet at C C. D is the camon or scraper. E is a canal or conduit for the slimed ore. In the three photographs given on the page opposite, ihe first shows the workmen mixing the charge, with the horses at work behind them. In the second, the men are mopping the floor of the pado and sweeping the amalgam into the basin or cajon, shown in the bottom illustration ; here the work of separating the amalgam is finished and the men are cleaning up. 1 ! PBir^-'------ Three Stages ;n the Patio Process '-^l **i. "Xt HOKSKS TRKAliiNi, THK Ch,\Ri;E '% n Ki. Camoxkko At the Haciciula di- Guailalupc, ['acluica chapter 19 THE CHEMISTRY OF THE PATIO PROCESS— CHEM- ICAL EQUATIONS— OBSERVATIONS OF HUMBOLDT —LOSS OF MERCURY— CONTRAST OF POLICY. HE Patio process has been used on a large scale and continu- ously since 1557, therefore it is probable that a great many have attempted, at various times, to investigate the theory of it; nevertheless, iew have been bold enough to publish the results of their investigations. In oflfering a few notes, it is vi^ith the hope, mainly, of helping the younger students in our profession. The right amount of bluestone'* is important, for if it be insufficient, the copper sulphate is converted into the sub-cxide, which reacts on the mercury so as to sicken it, covering it with a film. The bluestone consists of the sulphate of iron as well as . f copper, for it is formed by the roasting of chalcopyrite; these sulphates react on the sodium chloride so as to lib- erate hydrochloric acid, which, according to Ortega," first forms cupric chloride and then, in the presence "Magistral, an impure mixture of copper and iron sulphate, was for- merly employed. Bluestone, commercial copper sulphate, has replaced it in practice. " 'The Patio Process for .\malgamation of Silver Ores,' by Manuel Valerio Ortega. Transactions American Institute of Mining Engineers, Vol. XXXII, pp. 279-282. 1 I II 140 AMONG THE MINES OF MEXICO of mercury, cuprous chloride and mercurous chloride. The cuprous chloride absorbs oxygen and then re- duces the silver sulphide in the ore, with the forma- tion of mercuric sulphate and the liberation of the silver. Thus: 2NaCl + CuSO, = Na,SO, + CuCl, CuO, + Hg = CuQ + HgCl CuCl + 4O + Hr- -f- Ag,S = CuCl -1- HgSO* + 2Ag. On being liberated, the silver immediately forms an amalgam with the excess of mercury. On the other hand Bustamente" claims that the iron sulphate in the magistral is essential, the role of the copper being, in many respects, subordinate, al- though necessary, to the iron. According to his expla- nation, ferric chloride is formed; this, on being re- duced to a lower chloride, releases chlorine, which, while nascent, acts upon the silver mineral, transform- ing it to a chloride. A subsequent reaction with the hydrated oxides liberates the silver and hands it over to the mercury, for amalgamation. The copper sul- phate acts as a carrier of oxygen and the presence of 't is required to preserve the mercury in a metallic s. te. The old theory, to be found in most text-books, was that after the cupric chloride was formed, a re- action with the silver sulphide mineral, in the pres- ence of air, yielded cuprous chloride and argentic "'A Study of Amalgamation Methods, etc.,' by Miguel Bustamente, in Transactions American Institute of Mining Engineers, Vol. XXXII, p. 489. COMPLEX CHEMISTRY 141 chloride, the argentic chloride coming in contact with the mercury, so as to form an amalgam, together with mercurous chloride, thus: (1) CuSO,+2NaCl=CuCl,+Na,SO« (2) 2CuCls+AgjS=2AgCl+Cu,a,+S ( 3 ) 2AgjS+4Cu,Cl,+60=4AgCl+2 ( CuQ.+sCuO ) +2S (4) 2Aga+3Hg=Hg,a,+Ag,Hg. It is a complex bit of chemistry, rendered obscure by the lack of accurate data. The Patio process is rarely checked by systematic analyses and assays, so *hat, despite the three centuries and a 'naif during which it has been used in Mexico, there is but little evidence available. One or two points stand out clearly. If silver chloride be formed directly from the action of the chlorine liberated from the salt, and if this be a necessary chemical stage, why is it that ore containing hornsilver or natural silver chloride cannot be treated successfully by this method? If copper sulphate be the sole active agent in the magistral, why is it that the pure copper sulphate gives such poor results? If there is no direct chlorination of the silver, why is so much salt required? The first two queries have been answered; the last can bo '. cplained on the ground that the brine serves as a solvent for the cuprous chloride, rendering it more active as a carrier of oxygen. Humboldt makes several interesting remarks- concerning the process of amalgamation on the patio, "'Political Essay on the Kingdom of New Spain.' Black's transla- tion. Vol. Ill, Book IV, p. 268. R ''^* w. :«' 'r* 142 AMONG THE MIXES OF MEXICO as carried out during his visit to Mexico, a hundred years ago: "The process invented by the miner of Pachuca is one of those chemical operations, which for cen- turies have been practised with a certain degree of success, notwithstanding the persons who extract silver from minerals by means of mercury, have not the smallest acquaintance either of the nature of the substances employed, or the particular mode of their action. The azogueros (or amalgamators) speak of a mass of minerals as of an organized body, of which they augment or diminish the natural heat. Like physicians, who, in ages of barbarism, divided all -u'- ments and all remedies into two classes, hot and cold, the azogueros see nothing in minerals but substances which must be heated by sulphates if they are too cold, or cooled by alkalies if too warm. The custom which was already introduced in the time of Pliny, of rubbing metals with salt, before applying the amal- gam of gold, has undoubtedly given rise to the use of muriate of soda in the process of Mexican amal- gamation. This salt, according to the accounts of the azogueros, serves to clean and to unskin the silver, which is enveloped with sulphur, arsenic, and anti- mony, as with a skin {tililla or capuz), whose presence prevents the immediate contact of the silver with the mercury. The action of this last metal is rendered more energetic by the sulphates with which the mass is heated; and it is even probable that Medina only employed simultaneously the sulphate of iron and ii HUMBOLDT'S DESCRIPTION 143 copper and the muriate of soda, because he discovered in these first attempts, that salt was only favorable to the process in the minerals which contained decom- posed pyrites. Without having any clear idea of the action of the sulphates on the muriate of soda, he endeavored to recompense (refaire) the minerals, that is, to add magistral, to those which the miner considers as not vitriolic." The 'hot' and 'cold' condition — called calentum, or fever, and frio, or chill — are untechnical references to oxidation and reduction, the sulphates contributing oxygen as fuel to the chemical reactions, while the alkali of the lime, ashes, or cement copper employed to doctor a 'hot' torta, neutralizes any excess of acid sulphate. The idea that the silver of the argentite was coated with sulphur, which had to be removed to permit of contact with mercury, illustrates the ignorance of what constitutes a chemical compound. The sodium sulphate is formed by the reaction be- tween the "muriate of soda" or common salt and the copper sulphate, so that the addition of it simply anticipated a reaction consequent upon the use of magistral. The mention of "decomposed pyrites" suggests the agency of iron sulphate in the Patio process, an agency the exact working of which is yet a subject for deba^^e among metallurgists. Further on, he explains how, by the leaden look of the mercury, they inferred the commencement of chemical action; when a fine gray powder was sep- 144 AMONG THE MINES OF MEXICO arated from it so as to stick to the fingers, they said the paste was too 'hot' and they 'cooled' it by adding lime. If it preserved its metallic lustre, or was cov- ered with a reddish pellicle or film, if it did not appear to act upon the mass, the amalgamation was considered too 'cold' and they endenvored to 'heat' it {calentar) by mixing magistral. The "leaden look of mercury" is due to excess of copper sulphate, with formation of flouring mer- curic chloride, which, in the presence of sunlight and organic matter (such as the droppings of the horses or mules that trample the torta) is converted into oxide; this is almost insoluble in the brine, formed by the excess of salt, and in consequence it is apt to be lost in the torta when it is finally discharged after treatment. When the torta is cold, the mercury is apt to show 'flouring'; it is in minute globules that do not coalesce, being coated with a reddish film of copper sub-oxide, because there is not enough of the copper sulphate present to generate chlorine from the salt, so as to form cuprous chloride. At first the charge was mixed by the treading of a number of bare-footed workmen, but in 1783 Juan Comejo brought, from Peru, the i.ea of using mules. The Gove'-nment granted him a privilege for it. This decreased the expenses of the process by one- quarter. Then Humboldt continues: "It has been long proposed to cover the surface on which the pastes t A it rJ m THE WASTE OF MERCURY 145 repose with plates of iron and copper instead of flags; and it has been endeavored to stir the mass by work- ing it with ploughs of which the share and coulter should be made of the metals mentioned, but the mules suffered too much from this work, the schlich (slime) forming a thick, and by no means ductile paste." Finally, he concludes: "The process in- vented by Medina possesses the great advantage of simplicity; it requires no construction of edifices, no combustibles, no machines, and almost no impelling force. With mercury and a few mules to move the arrastrest we may, by means of amalgamation por patio, extract the silver from all the meagre minerals near the pit from which they are taken in the midst of a desert, provided the surface be sufficiently smooth to admit of the establishment of the tortus; but this process has also the great disadvantage of being slow and causing an enormous waste of mercury." How great this waste of mercury was, it is diffi- cult to realize today when the old tailing has been washed by several generations of patient peones, or else scattered abroad by the torrential rains of the tropics and the dry wind of the high plateau. They used eight parts of mercury to one of silver. At El Oro the mill of 100 stamps was run for six years with- out the purchase of a single flask of quicksilver. The tailing heap of the old hacienda — built 30 years ago — gave all the mercury wanted. In cyaniding the tail- ing, the mercury was dissolved, to be precipitated in I' ■ I .r' • I -rr ^ifiU i I ' 4 I i 146 AMONG THE MINES OF MEXICO the zinc-boxes with the gold. The precipitate was retorted in order to drive off the water and the quick- silver. Out of a retort of 1,000 pounds there would be obtained 150 pounds, or two flasks, of quicksilver. Another suggestive incident may be mentioned. Nearly two years ago, when the mechanical ploughs (repasadoras) were installed at the Loreto mill, a cement floor was laid down, and in excavating for this purpose a big find of quicksilver was made, the earth being saturated with it. It is said that mercury worth more than 30,000 pesos was obtained. As Humboldt said, the Patio was successful de- spite the ignorance of any chemical reactions in- volved. It is only recently, when the process is being discarded for more effective methods, that the chem- istry of it has been investigated intelligently. As used for 350 years it was an empirical process, regulated by the experience obtained with the particular rre of each district. The Patio process was invented when men, horses, and time - ere cheap, when there was no haste to realize on the ore in the mine. And this spirit survives; when I asked one of the Mexican engineers why they did not exploit a certain rich mine on a larger scale, he said that the shareholders did not care to rush the production because they feared the mine might be worked out toe soon. This is the European idea of fifty years ago; the opposite of it is the American notion that it is best to gut a mine i . • i! w if . T'lF ■!. ;lr ail < < i n \ I t 1 '.{ i ai ( ■i! I iui DIFFERENCE OF IDEAS 147 evpeditiousiy and make the maximum money in the minimum time. Both extremes are extravagant. Pachuca affords examples of other methods be- sides the ancient Patio process. Some of these I r.hall describe in the next chapter. ' ^.."^Jj>'^4fcS:"Ji^';?•iJI^ /' chapter 20 I A^- ' ih, r i riin OTHER METALLURGICAL PROCESSES - THE H\C1ENDA LA UNION -KROEN'CKE'S METHOD - TLMJE-MILLS-THE BARREL PROCESS-FRANCKE'S PROCESS -CHILEAN MILLS -RETORTING THE AMALGAM — THE PLANILLA. T the Hacienda La Union there is much that is interesting to the metallurgist. The process is that of Kroencke, used in Chile, but modified by the manager, Francisco Narvaez, formerly a captain of artillery and graduate of the military engineering school of Chapultepec. As a military officer he visited the United States three years ago, and, be- coming much interested in niclu'Uir^ncal pr;;ct?ce, he resigned from the service to undertake the work for which he has since shown so much aptitude. The scheme of milling involves first a Sturtevant roll-crusher, which reduces the ore irom 3 or 4 inches to ^-inch diameter. An Imperial shaking-screen sizes the material to 16 mesh; the undersize is fed into an Abbe tube-mill ol 5-foot diameter and 22 feet long, while the oversize passes through rolls without springs, with 14 by 27 inch faces (made by the Denver Engineering Works). The amount of iron that gets THE CHILEAN MILL 149 into the pulp is only 2 per cent ; this fact is important in view of the chemical treatment that follows. Capt. Narvaez was led to adopt this method by reading the book on 'Ore Dressing,' by Robert H. Richards. Later on, without stopping the regular operation of the mill, he intends to replace the barrel-amalgama- tion process by cyanidation; as far as grinding is con- cerned, his results indicate that Chilean mills will more than hold their own against the competition of newer devices for pulverization. They permit of a very fine grinding at a low cost per ton. 7rom an average of thirty sizing tests, made on the product of the Chilean mill at this hacienda, Capt. Narvaez ob- tained the following results: Assay in Percentage silver, of assay-value Percentage. Grams. retained. riner than 200 mesh 80.00 1.290 93.65 Between 200 and ISO mesh 4.75 626 269 ISO ■ 100 •• 13.45 385 0.47 100 " 80 " 1.50 355 0.48 80 " 60 " 0.41 346 0.01 Tiie original a?say v">f the ore gave 1,102 grams per metric ton. One of these mills, for example, worked from February to June without stopping once for re- pairs; and with the ordinary unskilled labor, it ground 15 to 18 tons per 24 hours from 1^-inch size to the fineness recorded in the tests just quoted. The cost per ton did not exceed one peso, or less than 50 cents per ton. At the time of my visit there was one Krupp tube-mill, with other foundations ready for the Abbe I 150 AMONG THE MINES OF MEXICO tube. The Krupp tube crushed 50 tons to 100 mesh in 24 hours. It was preceded by a Krupp ball-mill, which reduced the ore from 1 /2-inch size to 24 mesh. It is necessary to grind dry, on account of the barrel process, which constitutes the main feature of the treatment. With the use of Chilean mills, as at the time of my visit, it was necessary to dry the product. Both ball-mill and tube work dry. Silex linmgs m the tube last three years. The use of the Chilean mills yields iron that becomes oxidized by the water, while the iron worn away from the balls in dry crushing through the Krupp mill, is in a metallic condition and in an amount suited to the later chemical reactions in the barrel. The ball-mill is charged with four balls of eight kilograms each per day, this representing the iron abraded from the balls themselves and the lining also. For setting the silex lining in the tube, a com- mon cement with two parts of sand is used; it sets in three davs. Trouble has been made by the fact that some of the sectional pieces of lining are not cut to the right curve; however, only three dropped out after being in use for a month. The flint pebbles are bought from Indians, who will not divulge the lo- cality where they find them. They are paid 35 pesos per ton, while the imported pebbles cost 75 to 90 pesos per ton. The tube has no screen, the material passes through the length of it and is then discharged. In the new plant as it will be re-arranged, the Krupp ball-mill will deliver its product to the Abbe tube, for re-grinding, and both will work wet, instead 7T* 7 %JR BALL-MILLS AND TUBE-MILLS 151 of dry. The ore that goes to the Chilean mills will be crushed to 1 V: 'nrh. size in a breaker and from the Chilean mac' les tht pnif will be pumped direct to the vats and c/rriidec]. ]•" om the day (in January, 1906) that E M. HaiT'iltf n, associated with Charles Butters, made a c;<»:-Me test on the ore at this hacienda, Csipi. Narvaezhas made more than 200 tests, obtaining an extraction of 98.127o on the silver and 88.4% on the gold. He believes that extraction of the gold is less than that of the silver because the gold is encased in the pyrite and, to liberate it, re-grinding is imperative. But the ore contains only 5 grams of gold per ton, therefore it remains yet to be proved, by further experiment, whether it will be necessary to re-grind more than 207o of the ore. It was the custom formerly to use the camonero to move the product of the Chilean mills onto the /)^//c, where it was allowed to dry in the sun, but the change to dry crushing will obviate the necessity for this prac- tice. At the time of my visit, the Chilean mills were being operated without screens, the discharge being by overflow, thus saving labor while using a great deal of water, of which there was plenty. The tires on the Chilean mills are changed so as to equalize the wear; they last two years; the dies last only about eighteen months. Each mill requires 10 h.p. The Fraser & Chalmers, or Union, type of Chilean mill, modeled after Walker's patent, gives good service, grinding 15 tons per day; those of other makers treat only 8 or 9 tons, because the runners do not maintain t i; \ 1 t, i f .u ■!!!« 152 AMONG THE MINES OF MEXICO a vertical attitude. Seven Chilean mills ground 60 to 70 tons per day, while the Krupp ball-mill crushed 50 tons per day of 24 hours. The product from the grinding machinery goes to the barrel-room. There arc 13 barrels, originally made by Allis-Chalmers and since modified on the spot. Each barrel is beneath a hopper that holds a charge of 4.7 tons. As this is filled by the cars (each carrying half a ton) a grab sample is taken to deter- mine the percentage of moisture and the richness in silver ; from the aggregate of all these samples a mean of the iron assay is obtained for the week, so as to indicate if the amount be sufficient to effect precipita- tion; if not, zinc is added in order to help precipitation and also because it has been observed that the gold recovery is better when zinc is employed in addition to the iron. The cuprous chloride is proportioned to the amount of -Mver amalgam in the barrel, decreas- ing from, say, (>0% Ciu.CU at the beginning of the month to 22 or 24::: at the end. The silver in the charge is precipitated on iron. The barrel treatment consumes eight hours ; it requires four hours to charge and discharge. Mercury is added half an hour after the treatment has begun. Salt is added in the ratio of 27 kilograms per ton of ore ; no more copper sul- phate is added than that required when making the copper chloride solution. The loss of mercury per month is 800 grams per kilogram of silver; the loss of silver is 6.88 to 9% when treating three charges per day. THE BARREL PROCESS 153 The barrels are washed out once per month, dur- ing the remainder of the time the silver amalgam accumulates ir-He of them; it is taken out every other day, in suon an amount as to yield 250 to 300 kilograms of silver bars. From the barrels the pulp goes to six washers or agitators, and from them to apuros (or wells) un- derneath, where the silver amalgam is collected. Thence the tailing passes outdoors to a crude form of conical buddle. The 2,300 to 2,500 tons of tailing treated each month contain 110 to 120 gm. silver per ton and yield 25 to 30 tons of concentrate assaying 2 to 3 kg. silver and 30 to 40 gm. gold per ton. When CU2CI2 is added, there is a formation of AgCl and sometimes of HgCl; then if zinc (in the form of strips of metal, not shaving) is added, the metallic silver is precipitated and also the mercury. Sodium hyposulphite was tried, but, although useful, it was not found necessary. The purpose of it was to regenerate the Hg from the HgCl formed, and the same end could be gained by the motion of the pulp in the barrel. If there is enough iron in the pulp, it will precipitate the silver, but the amount of iron is not under control, hence the addition of zinc if the iron be inadequate. From the wear of the lining and of the balls in the Krupp mill, Capt. Narvaez was get- ting 600 gm. iron per ton of ore, this being the amount which practice has demonstrated to be neces.sary. Whenever, for any reason, the amount is less than as specified, zinc is added. Experience has proved 1 ] ii u\t^^ 154 AMONG THE MINES OF MEXICO that, although 1,200 gm. iron is adequate to precipi- tate the silver in a charge of two tons of ore and give bullion 999 fine, yet zinc is always needed in order to increase the gold recovery. If this be done, the bul- lion will assay 960 gm. silver and 2.8 gm. gold per kilogram, while, if the zinc be omitted, the gold will not exceed one gram per kilogram. The total extraction of silver by this barrel process is 95% ; that of the gold is from 35 to 75%. In the concentrate, 5'."' more of the gold is saved. The gold is to the silver in the ore in tlie ratio of 5 to 1,000. The ore treated at the mill is wjrth as delivered 23 to 25 pesos per ton, the cost of extraction {maquila) last year was 10.50 per ton, and the profit 8 pesos per ton. The ore assays generally 1.2 kg. silver, equal to about 41 pesos per ton. The bulk of the ore obtained from the mines of the Real del Monte Company is similar to ♦^hat treated at the Hacienda La Union, although in the Corteza mine of that company there is produced the class of manganese ore called 'quemazones,' on account of its black appt.irance. Such ore is not suitable for the process o'' amalgamation because of the loss of mer- cury, following upon the familiar reaction in which a mixture of salt, manganese dioxide, and sulphuric acid evolves the chlorine destructive to mercury. At the time of my visit, this ore from the Corteza mine went to the Hacienda de Loreto; it was a black sili- cious material containing 87o manganese dioxide. The treatment to be described has ceased lately, the WW % •m'^ ■flWita REFRACTORY ORE 1 55 mill having been utilized to test the adaptability of the cyanide process to this class of ore. At first the idea was to erect a ball-mill, followed by a re-grind- ing tube, as at La Union, but later it was decided to install two sets of rolls, of the same dimensions and running at the same speed, the first pair for reducing the ore from 3 to ^-inch and the other for grinding to 16 mesh; between the rolls there is a trommel, and thence the material goes to the tube-mill. Trouble was caused by the moisture in the ore, a coating be- ing formed on the silex, requiring removal with a chisel. I shall now describe the process for which the original plant was built; it was a modification of the Francke process, originally developed in Chile. On arrival, the ore passes through a Blake crusher and then it is fed to the rolls, which deliver it to a trommel provided with a 70-mesh screen; the undersize goes to the bins, while the oversize passes to a tube-mill {cilindro remolcdor), also made by Krupp, where it is re-ground with flints {piedras de chispa) at the rate of about 40 tons per day. Then it joins the previous un- dersize in the bins. Next come four calcining fur- naces, each with a capacity of 20 to 30 tons per day. The charge of 10 tons is given 1 1/2 hours. Salt is added in the proportion of 18 kilograms per ton of ore. The calcined product drops below the furnace and is taken in wheelbarrows to the cooling-floor. Here it is shoveled into vats {tinas de Bolivia) where it becomes mixed, through the agency of revolving arms, with < I mmm- 'S i : 'V 156 AMONG THE MINES OF MEXICO \ f ' cupric chloride (CuClj) and mercury. Copper plates placed along the sides of the vats catch any gold in the pulp. Each vat is 3 metres deep and 2>< m. in diame- ter. During the treatment, steam enters through the bottom. Three charges of nine tons each are treated per day. Then, after four hours of mixing, the pulp is discharged from these vats, through three openings at successive levels leading into pipes that empty in a mercury trap {apuro) outside. Here the silver amal- gam is caught. The tailing passes on to two settlers, without further addition of mercury, the purpose be- ing to arrest any amalgam escaping from the preced- ing operation. Below each settler there is an apuro, which finishes the treatment. Only one shift of 12 hoars (by day) is employed. Two men attend to each furnace; these also do the wheelbarrow work. Threemenattend to thepans; in addition, there are two roustabouts and one foreman. Each charge is not followed by a clean-up; the amal- gam i^; allowed to accumulate. The mill was idle at the time of my visit; it is probable that there was a heavy loss through mineral which was ground fine in the tube and then pulled by the strong draft into the chimney of the calcining furnace. Also there is likely to have been loss of silver by volatilization as chloride. The machinery is operated by electricity, and m contrast to this flagrant modernism is the shrine in the roaster-house, with its picture of the Virgin. In other parts of the establishment there are crosses, SHRINES AND SMELTING 157 decorated by withered flowers. Everywhere in the hacienda there is an exuberance of masonry; the works are enclosed by massive walls, like the ram- parts of a fortress of the old-fashioned kind. Such ore as does not contain manganese oxide, and comes from the other mines operated by the Real del Monte Company, undergoes direct concentration, followed by amalgamation. This quartz ore is re- duced by two Blake crushers and then passes to 14 Chilean mills, which discharge through 80-mesh screens. The feeding is done by automatic (the Hendy Challenge) machines. From the Chilean mills the pulp goes to 32 Johnston vanners, which extract the pyrite, not only to get at the gold that is inti- mately associated with this pyrite, and to take out half the silver in the ore, but also with a view to sim- plifying the Patio process, which follows and which would otherwise need the addition of more chemicals. The 14 Chilean mills grind 800 to 900 tons per week; the crude ore contains 1 kilogram of silver to 5 or 6 grams of gold; the pyritic concentrate represents 4 to Ay2 per cent of the crude ore; the richer concen- trate, with 9 to 10 kg. silver and its proportionate amount of gold, is shipped to Germany, while the poorer, with 4 to 6 kg. silver, is sent to the smelters at Monterrey and Aguascalientes. The tailing from the vanners goes to big ponds, where it settles to a thickness of 8 to 9 inches of pulp. The camonero, or horse with the drag, is employed to move the slime to the different rectangles in which >? If ! 5 "I l!l I 158 AMONG THE MINES OF MEXICO the mixing stage of the Patio process is carried out- There are 17 rectangles (50 metres wide and 80 m. long), for the treatment of as many charges or tortus, each being equal to 220 to 300 tors. The mixing is done, not in the old way by horses, but with a me- chanical harrow, such as has been described in con- nection with the Hacienda Guadalupe. In this case also, it seemed to me that the mechanical mixer failed in its service; the material was too wet, the harrow omitted to turn the palp over and simply passed through it, without causing aeration. Moreover, as the harrow cannot be made to scrape the floor, there always remains at the very bottom an inch or more of pulp, which is not moved and which, therefore, escapes metallurgical treatment. The clean-up was done as at the Hacienda Guadalupe, so that the description need not be repeated. The retorting is worth noting. The bricks of amalgam are arranged in the form of a pyramid of about one ton weight standing in an iron pan, the bottom of which is perforated. A hood is then dropped over the amalgam; a flue from the furnace enters through an aperture near the base of the hood. The mercury, as it is distilled, passes out at the bottom into a stream of cold water, by which it is condensed. The ratio of mercury to silver in the amalgam is as 8tol. At the Progreso mill, which was built by that rep- resentative Amfrican millman, M. P. Bess, there are 50 stamps, followed by four Kinkead mills; the lat- t 1 !'■. .1 -H Two VlK\V> OF Mk\ (' KkATlNt; TIIK Pr.ANM.I.A AT PaCHUCA (T\. ■ IT A f^mff THE PLANILLA «59 tcr is a machine for re-grinding. Then come two chemical mixers, 16 p?ns, and 4 settlers, followed by 4 New Standard and 6 johnston concentrators. Just outside the mill I saw the Mexican method of concentration by the planilla, or little plane. The material is heaped up at the head of an incline plane. 8 to 10 feet long, 4 to 4J^ feet wide; the operator throws the water with a horn, by successive regular sweeps of his arm; at intervals he scoops up the ma- terial with a wooden shovel, and as the heading be- comes cleaned (or concentrated) he moves fresh ma- terial to the top of the incline. Mexicans can be seen operating the planilla along the beds of streams that receive the tailing from the mills st Pachuca and Guanajuato, as the accompanying; photographs show. The device resembles the 'tyes' or straight buddies employed for the treatment of slime in Cornwall. Hi '% ^ i 1 ' ft ! I • a Cbaf ter 21 FIRST Gl.IMPSE OF GUANAJUATO— THE HISTORY OF LOCAL MINING— THE \ ETA MADRE AND ITS BONANZAS-RICH MINE-OVVNERS-THE COUNT OF VALENCIANA— STORY OF THE CHURCH-DECA- DENCE OF THE DISTRICT. T is uncomfortable to arrive at one's destination just before (lawn, but sometimes the dis- ci Mufort is not without compen- sation. Owing to the wretched train service between Mexico City and Guanajuato (406 kilo- metres or 252 miles), the trav- eler reaches Silao at 1 a. m. and then, changing to a branch railroad 14 miles long, he arrives at Marfil at 3 A. M., whence a horse-car bears him to Guanajuato, a distance of four miles and occupying an hour. The car is pulled by mules, at a sharp trot, along a winding tramroad that follows the boliom of a ravine; there are glimpses of high walls, dark archways, and silent courtyards, an occasional hooded figure comes within the rays of the feeble lamp at the front of the car, other lights are infrequent; soon the tram penetrates a thickly built town, the mules awaken echoes as they scramble over the cobbles; the reverberations are lost in narro , . alleys, but there is no sign of life, save the EARLY MORNING AT GUANAJUATO l6l tired watchman who blows his whistle to prove him- self awake and to prevent the other watchmen from falling asleep — incidentally telling any prowler just where to avoid him. The car goes up a steep gradient, almost brushing the walls that look down on either side, around sharp turns that threaten a capsize, over a narrow bridge and along a stream flanked by rustling trees. The journey is over. A friend conducts me to a lofty wall, a dorr opens, we are in a moonlit patio, in front of a white colonnade, in that light as poetic as the moonlight itself, the effect of which is Iieightened by a sound as of surf borne inland from the shore; it seemed the voice of the distant sea, but it was the .luffled roar of a starif-mill. However, that rhythmic swell served to put ii' sleep, deeply grateful for a little rest after the iit> 'ime travel of tlie night. This was part of the compensation, but tlie best of it came on awakening three hours later. It was a sunny morning, with all the coolness of the tiighlands and all the fragrance of the tropics; going on the portico, I found myself overlooking a ' \vn behind which extended an array of steel vats indicative of a cyanide plant; to the right were the white-washed houses occupied by offices, and to the left rose a loftier building — audibly, a stamp-mill. The whole foreground was surrounded by a wall on which the sunlight played gladly. Beyond were low roofs and trees, rising on hillslopes, partly under cul- tivation and leading to a brown ridge whose clear-cut edge was silhouetted against the blue of a perfect sky. i ^ J K 'h ' H'l 162 AMONG THE MINES OF MEXICO \t It was the Hacienda San Francisco de Pastita, an old Mexican reduction works, now transformed to mod- ern methods, it was an island of Anglo-Celtic energy in the midst of an old Spanish mining centre, and the spirit of the men and the machinery of this new mill of the Sirena mine was to the old era represented by the decrepit town outside its walls as the invigorating sunshine of this bright morning to the dark weariness of my experience during the night that was past. Guanajuato, in the State of the same name, is a city of 50,000 people, situated at an altitude of 6,600 feet among the foothills of the Sierra de Santa Rosa. The air is dry and clear, colors are vivid, lines are defined, and the sunlight is brilliant. The town is not without character, for it is adorned by many churches and other impressive buildings; it lies ensconced among terraced gardens and brown hills, on the higher slopes of which stand the battlemented en- closures and picturesque churches of historic mines. Their story is worth the telling,'* The history of Gunnajuato begins in 1526, six years after the Spanish Conquest, when the mineral wealth of Mexico was being eagerly sought out by the hardy conqvistadores. To the north, the mines of Zacatecas and San Luis Potosi had been uncovered; the road to them, from Mexico City, passed near the site of Guanajuato, but in those days it was danger- ous to depart from the highway, for the natives, the "And in the telling of it, I am indebted for many of my data to Capt. W. Murdoch Wiley, who has studied the records. ^9" «« «mi FIRST DISCOVERIES OF ORE 163 Chicemecas, were unfriendly. A fort was built at Santa Ana, and this became the first European settle- ment in the region. Prospecting became more prac- ticable, but no mineral discovery of importance fol- lowed, until 1548, when the silver mine of San Bernabe was discovered at La Luz, six miles from the Guanajuato of today. Two years later rich ore was found on the hills adjacent to the present city; the Rayas mine being started by a Spaniard of that name. The document that registered this fact is the oldest in the archives of the Court of Mines at Guana- juato. It was not until nine years later that the work done at the Rayas and Mellado mines led to the recog- nition of the mother vein, la Veta Madre. The ore was mined for a width of 100 feet, so wide indeed as to postpone further exploration along the course of the lode. But the ore found by the Mellado shaft, in 1559, suggested the idea of continuity and caused an extension of activity, so that it was not long before mining operations were under way from the Tepeyac to the Sirena workings. To those of us who regard the discovery of the Comstock, less than 50 years ago, or even the event at Sutter's Mill, 58 years ago, as a historic event, it is worth noting that the happenings briefly chronicled in the foregoing lines occurred be- fore 1600 — before the first settlement of Virginia, shortly after the sailor captains of Elizabeth had swept the Spaniards off the seas, and just about the period when Shakespeare and Bacon were busy pre- paring documents of controverted authorship. f ¥\ !H I P\ h i 164 AMONG THE MINES OF MEXICO By this time the population of the town had grown to 4,000, and it continued to increase as vil- lages sprang up around the individual mines. In 1619 the town was granted a patent, becoming dignified by the name of Villa Real de Guanajuato. This was a year before the landing of the Pilgrim Fathers at Plymouth. The industry grew; amalgamation was intro- duced from Pachuca, the Patio process being first employed at the Hacienda de Duran, just below the Rayas mine. The best selected ore was smelted on the spot and, considering the high grade of it, the slag was surprisingly clean, for the remains of old smelter dumps below the Rayas and Cata have been found to assay only two ounces of silver per ton. Forced labor, o' course, was employed, and two proclama- tions ^ear testimony to the brutality of it, for one of them prohibited the indiscriminate sale of Indians and the other forbade the branding of a slave in the face. Within a century, that is, by 1700, the population was quadrupled and the area of the camp was doubled. Immigration was slow, for Spain was a long way oflf in those days of uncertain sea voyages; the transport of supplies was both laborious and hazardous, the whole European population of Mexico was still meagre, and mining methods were as yet primitive. But the discovery of gunpowder and its application to mining, the introduction of pumps and the accumulation of wealth among the mine owners. •'!',' 2)5 , jui,ij< . ..AtiJM.x mmrmr^m/fmmi p» nrnpF MINERS THAT WERE ENNOBLED i6S r all tended to enlarge the scale of operations until Guanajuato, toward the end of the 18th century, be- came one of the great mining centres of the New World. Tiie big mine owners won such wealth that, like their modern successors in Nevada and Montana, they became legislators and were given seats in high places; they were granted titles of nobility and en- livened the ranks of Spanish aristocracy. Jose de Sardaiieta was created Marquis of Rayas; Francisco Mathias, the owner of the Cata and Secho mines, be- came Marquis of San Clemente and Viscount of Duarte, while Antonio Obregon, the discoverer of the Valenciana, became Count of thai name. It was a great day for these mine operators. They were con- sulted in affairs of State, just as nowadays men who contribute to campaign funds are likely to possess what Mr. Mike O'Flaherty trrms 'infloo-ence'; they posed as Providence to the poor people, for when times were hard and the corn crop was a failure, they provided work for the needy and saved them from starvation. It is said that the big galleries and com- fortable cross-cuts, large enough for the passage of a broad-gauge locomotive, tnat surprise the mining engineer when he first visits Guanajuato, are the evi- dence of work carried out with such charitable intent. When an unusual bonanza was struck, the for- tunate miner built a shrine or even a church, in token of gratitude to his tutelary saint. Thus one Sarda- iieta advanced an adit so as to cut the Santa Anita *f'H!U.- -ti i66 AMONG THE MINES OF MEXICO ore-shoot on its dip, but failing to reach this point before he died, he told his son to continue the good work. He did, and found the bonanza of Santa Rosa, which made the Rayas mine famous. This Sar- daiieta became Marquis of Rayas and erected the monumental buildings whose flying buttresses and sculptured portal, surmounted by the figure of the archangel Michael, are today the glory of the San Miguel shaft-house. The church of Valenciana is another such me- morial to successful prospecting. This edifice was consecrated in 1778; though badly cracked in many places and doomed to destruction, its fine harmonious facade in carved can/era was rendered doubly impres- sive when I saw it at the end of a day's investigation of the old mines, and, mindful of a most romantic chapter of mining history, watched the shafts of sun- light suffuse the old church-front with a glory richer than the treasure vault of silver that it commemorated. The church was built by Antonio Obregon, a Spanish miner, who discovered a great orebody north of the Cata mine, in ground that had long been held to be barren. He had thought otherwise and prospected for three years, until penniless. Then a merchant of Guanajuato provided some funds, until he too was bankiupt. Oth rs were persuaded to share in the venture, only to lose tbcir money, until Obregon won the name of el tonto (the fool) de Valenciana. But his justification came at the end of seven years of persevering work, when he broke into the biggest wmm ■p M 4fP Thk Flying Bittkessf.s of San Mir,i-Et. de Rayas ■ I' ^l\ ^ t i \iM : i lihi'^ \ A'-P i ^\}^i o *^^ffflf? ■P^ THE CHURCH OF VALENCIANA 167 bonanza ever found on the Veta Madre. It was much more than his fondest expectation, for, while the Tepeyac had been worked in a desultory way from 1590 and the outcrop of that vein in the Valen- ciana ground has yielded some ore, it is doubtful whether any such ordinary body of mineral could have repaid the long and expensive search made by Obregon and his backers. In a few months all the expenses of years were repaid and eventually Obre- gon became, the chronicle says, the richest man in the world, at that time. The immediate origin of the church is told thus: On the ground near the mine, Obregon marked out an irregular quadrangle within which the miners were told to place a handful of rich ore, which each man was allowed, for this exceptional purpose, to bring out of the mine. It was a custom that recognized the innate tendency of the miner to purloin a little — a specimen or a sample — of the rich ore that he was helping to extract; and by requiring his men to donate that larcenous portion of mineral for the benefit of Holy Church, Obregon was finally able to do a great deed without unduly taxing his own receipts. The quadrangular area as marked was eventuSiy covered three feet thick with rich ore; this was sold and the proceeds of it were employed to build the church. It was begun in 1765 and finished in 1785; it is said to have cost $1,000,000, which was about equivalent to the annual income of Obregon. He made gifts to the Crown and, becoming the wealthiest subject of Spain, he was made Count of jl V 1 ■ t. ■ r i68 AMONG THE MIXES OF MEXICO Valenciana. This was at the time of the American revolution, and since then we have had many a Monte Cristo among mining adventurers, a motley crew of ill-balanced men, from vulgar spendthrifts like Tabor and Barnato to great-minded builders of empire like Cecil Rhodes and Alfred Beit. mm 'M '■■•■■ill nil f J u i .i ' .■■t- pry"!g*''^wPffgB— wgjgw! chapter 22 GUANAJUATO AT ITS HEIGHT — DEEP MINING — VISIT OF HUMBOLDT- DECADENCE— LA LUZ— THE REVIVAI^AN AMERICAN INVASION— THE STORY OF MODERN PROGRESS. T the end of the 18th century the mines of Guanajuato were the foremost of their kind. It was then that the Valenciana shaft was sunk to 1,800 feet, and it is still the deepest in the dis- trict. This work, done by Obre' _ _ gon, was completed in 1785 at a fabulous expense. It is said to have cost a million, though even this expenditure becomes small rela- tively to that of the Combination shaft, sunk on the Comstock lode, in 1881 ; this was 3,100 feet deep and cost $6,000,000. However, the cost of the big shaft of the Valenciana was offset by an extraordinary pro- duction, stated at 300,000,000 dollars, most of it ex- tracted (Jfiting the la^t half of the 18th century. This figure corresponds to the total output of the Com- stock up to the time when the lower workings were abandoned, in 1884. On August 20, 1804, the King's tax, amounting to the sum of 2,648,866 dollars was paid. As this represented one-fifth of the yield for a period of five years, it serves to substantiate even the ^^ mmfimm r-^^-. m It •; i ! i^ {•>-i| l/i I/O AMONG THE MINES OF MEXICO extraordin.iry statistics of these old mines. The other mines on the Veta Madre and those on the La Luz veins also produced enormously at this period, so that the population of the district at the beginning of the 19th century had increased to 100,000. This was the time of Humboldt's visit. He says that "the whole vein (the Veta Madre) of Guanaxuato" may be estimated at four ounces of silver per quintal of mine- rals." As a quintal is 100 pounds, this means ore aver- aging 80 oz. per ton of 2,000 pounds. Then came the long years of the revolution against Spanish domination. In 1810, when at the height of her prosperity as a mining centre, Guanajuato was attacked by the Republican forces under Miguel Hidalgo, a priest, who became the hero of the Mexi- can war of independence. There was desperate fight- ing and the city was captured. The entire fabric of government and of business went to pieces. The warring factions made forced loans on the min^^s, horses and provisions were wantonly seized, life be- came insecure, so that mining operations were dis- couraged and all work of importance was discon- tinued. Deep work ceased entirely, no shafts were sunk, and the production of ore was reduce* to infie- quent shipments taken from supporting pillars and from the sides of old stopes. Even such decadent mining soon became insignificant as the miners were driven toward the surface by the slowly rising water. ' It is always spelled with an x in Humboldt's memoirs. I' M l\ fk A .. WWPIF'^EgBaiWIP'Wgg z PT'S* iH \\u ' '■ |!.1 i\ DURING TH! REVOLUTION! m it was at this period of general lawlessm ^ that the heavy wails wi'h watch tov ers vvere bui.t .round the mini"^. ui til v ci property of consequcr ha'' lue look oi ' fonress. Simiiar pro'cction was pivi.n to the reduction w irk, which be me fonitied enclo- sures, tor the p.No.^ .vere frequ^inly rofi ed ■' their c!' rin-up * roviiig !• nds ' lonq^ing to both tactions, viichm hener**ss)ties< th* r organization an ex- tor a .rener; battlcnu-nte'' anajuato an ;nd afford ronia "ic tiii velvc '■^ 1' in th wr.ii r. >pi-! th*- in en. '1' pillage and munier. IS survive in the vie ty ue- this • riod of law! etting to mti es traditions. Spanish rule the first Mexi- ^qi ,r eai -cd uefore of Iturbide a; Mexico City, on Jul.. 21, 1822. '~>ur nl the population of Guanajuato d in Til of 1 ncs> • ca ci-i r iiu died t 2( AAj md mining almost ceased. Wit'- he ■■e with the result that two large companies were f rmed, the United Mexican Mining Association and the Anglo-Mexican Mining Company. They ac- luired several of the bigg^-^t mines on the Veta .""'.drv lesides others of the '.'ierra and La Luz sys- u is. The old workings were unwatered and the [iri'in: nc cm ju;> schemi s I a 17a AMONG THE MINES OF MEXICO w ,)7\ ^1]^ it' II ■ m!'.ls were renovated. But it was not smooth sailing for these EngHsh companies, there were periodical local insurrections, life and property were still inse- cure, and mining was attended by many interruptions ; for example, in 1832, one Ariste, at the head of a 're- generating army,' or ejercito regeneradoro, swooped down on the Rayas mine, then the property of the United Mexican Co. and lifted silver and corn to the value of 26,000 pesos. The mines of La Luz were in bonanza in 1842 and for many years after, so that Guanajuato itself be- came less important, but twenty years later Francisco Glennie took charge of the Rul estate and by his skill he made these mines on the Veta Madre more pro- ductive than they had been at any time since the palmy days at the close of the eighteenth century. The Valenciana was unwatered to the bottom at 1,800 feet and a new orebody was discovered in the Merced" vein. At the same time Glennie developed the Cata mine and found the rich Juanita" vein. When he became invalided, in 1890, another period of depression ensued at Guanajuato. All the com- pany work at the Valenciana was stopped and the water was allowed to rise. At the Cata, the water was kept down, but here, as at the Valenciana, the workings were handed over to the tender mercies of the buscones. These are 'tributers' on a small scale; they take a lease from week to week without any writ- " These were speci.nl segregations of rich ore in the Mother Lode. nP9B ENERGETIC PROMOTERS J73 ten contract and divide the ore they get with the mine-owner, who provides the tools, powder, and blacksmith. On each Saturday morning the buscon sorts his ore, arranging it in two equal piles, of which the foreman takes his choice on behalf of the owners of the mine. Of course, the buscon cannot aflford to explore, he does no 'dead work' ; and as he moves no more waste than is necessary, the workings soon be- come choked with refuse. He nibbles at every pillar left to support the old stopes, and causes caving that will close the mine or portions of it, permanently. And so mining came down to a dreary unprogres- sive level, with no new work and no fresh discoveries of ore, until, in 1898, another revival was inaugurated by the f iterprise of a few Americans. In that year the Guanajuato Consolidated Mining & Milling Com- pany secured the Sir na mine and erected a modern mill, under the direction of Mr. M. E. MacDonald, assisted subsequently by his brotlser, Mr. Bernard MacDonald. In 1902 the Guanajuato Power & Electric Com- pany was formed by a group of mining men at Colo- rado Springs, on the initiative of Mr. Leonard F. Curtis; he was ably supported by Messrs. George Bryant and George W. McElhiney, to whose financial ability are due several of the most important enter- prises in the district. As fuel of any kind was very expensive, the introduction of power at a reasonable price was an important step in the progress of min- ing. This was accomplished in November, 1904. I i 1 1 174 AMONG THE MINES OF MEXICO J •n The electric energy now used at every large mine in the Guanajuato district is obtained from the river Duero, in the State of Michoaca... 101 miles distant. This power at 185 pesos per h.p. year" replaced wood at 8 to 10 pesos per metric ton and stone coal, from Las Esperanzas, in Coahuila, at 20 to 24 pesos, delivered. The next enterprise of importance to be started was the Guanajuato Reduction & Mines Company. The history of the mines that it acquired has been mentioned; they included the property originally be- longing to Obregon, the discoverer of the Valenciana, and from his descendants by intermarriage they had passed to the noble family of Rul. In 1860 the Sefiora Perez Galvez, then head of the house of Rul, began a clever campaign, the purpose of which was to obtain avios or perpetual leases on these mines, including the Valenciana, Cata, Tepiac, and Mellado. By the avio she was able to charg<» all expenditures against the mines, crediting them with the money received from the sale of ore; by building large works or haciendas, bhe made contracts with herself to purchr v the out- put of ore, deducting high rates for trec»..nent and mixing the rich with the poor ore, ^o that the expenses of mining were always in excess and steadily in- creased the debt against the mines, while permitting of handsome profits at the haciendas. The options to these contracts or avios were acquired by Messrs. " This is the average price. The lowest price in the dist- ict today is $60 per h.p. year. -'^a^ene i*^.-a _ / THE AVIO COl TRACTS 175 Bryant & McElhiney, and transferred by them to the Guanajuato Reduction & Mines Co., which finally bought them outright. According to Mexican law, if at any time the mines get into bonanza, so as to make big profits from the sale of ore, the lessee has the right to take all such profits, without any division with the owners, until the entire accumulated debt — about six million pesos — is paid, thereafter dividing the further profits according to the terms specified in the lease; in plain English, the original ownership is a legal figment. Besides acquiring these old con- tracts, the promoters mentioned had the foresight to 'denounce' or 'locate' claims covering the dip of all the important properties on this part of the Veta Madre; that is, they secured the 'deep levels.' Finally, after expert examinations and reports had been made by such men as Carlos Van Law, Robert T. Hill, and Louis Noble, these properties and all their rights passed under the control of the Guanajuato Reduction & Mines Co., in November, 1904. Since then other ventures have been organized and started, but their story is in process of making and must be left to a later record. While the peso today is worth about half of a dollar, before the (lomonetization of silver they were about equal, for each contained about an ounce of °ilvcr. I -. -f-^^ »■'»'« ' ^KBTSSf. f\^ » "■' * copter 23 VISIT TO THE OLD MINES— A CAVALCADE— THE BUSTOS PLANT— MECHANICAL DEVICES AGAINST MANUAL LABOR— THE MOTHER LODE — SAN MIGUEL DE RAYAS. N the morning of November 2, a party was made to visit the old mines of the Veta Madre. We formed an imposing cavalcade, for it is the custom in Mexico for each horseman to be accom- panied by a mozo, who serves as groom on ordinary occasions, and is a courier and general servant when going across country to the mines at a distance. These men wear the wide-brimmed sombrero, fancy leggings, and big spurs, so that they are picturesque if nothing else, and on an occasion of pleasure snch as this was, they gave a touch of gaiety to a group of horsemen, most of who were as properly accoutred as in Chapultepec or Central Park. There were ten of us, and eight mozos, so that when we clattered down the narrow cobble-paved alleys of the old Mexican town, we made noise enough for a regiment, scattering care- less wayfarers and awakening echoes under arches that had seen many inv?sions murh less peaceable. The well-bred Mexican is a splendid horseman, but the inhabitants of such a town as Guanajuato are, of if \ I v. w -'za^-'i'.mKk" Amonc, Friknds at Gl'anajuato C, W. llrya.it. Bernard MacDonal.i, T. A. Hickar.l. F. J. Ilot'si.n. 1). J. Hutton, C. W. Van Law, M. ¥.. MacDonalil. Norman Ko*e. m:-' it. *i StkKI. OkE-HiNS ami liMTKKV lolMiATlONS (II THE BlSTOS MiLL THE BUSTOS MILL -^n course, content to go afoot, so that accompanied as I was by a group of engineers and metallurgists, it occurred to me that there was a simile to be snatched from the scene, the technical man being the fellov on horseback, progressing confidently (usually w less noise), while the rest of the world is content p > force to go on foot. Well, my friends rode several hobbies, not to mention spirited steeds; one of them was the application of the cyanide process to silver ores; and their horsemanship was good either way. On arrival at the lower end of the town, I was shown the Hacienda de Bustos, where the Guanajuato Re- duction & Mines Company is remodeling an old re- duction works to the needs of a modern equipment, as the accompanying photograph will illustrate. This hacienda is about a hundr-d years old ; in pulling down the walls to make room for the concentrator floor, there was found a system of older unconform- able foundations, and in the angle made by two walls of ancient date, the workmen unearthed half a dozen complete skeletons, with a bullet hole in each skull, and so placed as to indicate that the originals were pistoled while lying down. However, this gruesome find did not hold our attention long, for the founda- tions of the new stamp-batteries and the steel framit g of the ore-bins afforded more cheerful subject for thought. In the erection of the Bustos plant, bedrock was everywhere available, and the heavy masonry walls were built cheaply by Mexican labor, which is par- 178 AMONG THE MINES OF MEXICO ticularly skilled in such work. Each stamp weighs 1,050 pounds. The mortars are of El Oro type and weigh 9,000 pounds; they rest upon massive concrete blocks laid in Dyckerhoff cement. The concentrator room is spacious, being covered by a well-designed roof-truss of steel construction. The tailing from the Wilfley tables runs into a concrete launder, which extends down the longer axis of the concentrator room to the centre of it, delivering its contents to a tunnel at right angles and thence to the cyanide annex. While the plant was in course of construc- tion, a 5-stamp battery, with its cyanide annex com- plete, was being employed for testing the various ores destined to be delivered to the works when finished. Even when the 80 stamps are at work, this small addi- tion will be kept in service, for experimental purposes. In the concentration department of this testing plant there is a Wilfiey table, a Gilpin county bumper, and an Overstrom table. After being crushed under the stamps, the pulp passes over one of the three ma- chines just mentioned and then to a sump, whence it is pumped 60 feet to cone-separators. The sand undergoes percolation in vats 8 feet deep and 8 feet diameter, provided with, the Butters hydraulic dis- tributor. The slime is agitated in vats 9 feet deep and 8 feet diameter; one vat using the Hobson aero- mechanical agitator nnd the other a Butters pump with mechanical stirrers. Thus the testing plant is designed throughout to duplicate the conditions under which the big mill is to be operate . - - 11. -^TS- \iliiii ■ VI- 1 livmiaii^ ■IShB'iK'MiBes&RXtii rs" Thk Ga'Eway of the Rayas Mine = "ffiKB iSHt'.j'is^'aara' ^.rw, ■ ill' m 1 \ 4*^' 1 '■■ J 1 ■ : ■ - \ '^ % i • ^=r:i . \ - 4 ^ -,v_ ■..■■S 4 ^■^^ ■' " T-4L I ' ^^^^K^H|^^^PHi^H ! n » i i iWt i •II f fcA^t y^w% STEEL ORE-BINS 179 The Bustos mill is planned so that it can be doubled conveniently; in fact, excavations for that purpose were under way at the time of my visit. A sufficient space will be cleared at the back of the ex- isting plant to allow of the erection of a second row of 80 stamps on the other side of the bins. A concen- trator room, identical with the existing one, will be added, so a^ to make the plant a 160-stamp mill of back-to-back construction. Owing to the high price of American lumber when delivered at Guanajuato, and the poor quality of the Mexican material, it is considered economical to use steel. The skeleton of the bin is of 15-inch channels placed back-to-back in bents that are on approximately 6-foot centres, the vertical channel posts being tied together at the bin-floor level by two 15-inch channels, which are braced from the feet of the posts by inclined struts composed of four 5 by 3^ by %-inch latticed angles. The thrust that these inclined struts carry to the feet of the posts is taken by two 8-inch channels acting as a tie between the feet of the posts, thus trussing the whole and making the strains on the masonry wholly vertical. As the weight in the bin is about 2,500 tons, exclusive of the bin itself, the feet of the columns are supported upon a grillage of six 5-inch I-beams, two feet long, held together by platen riveted to the top and bottoms. This rests directly upon the masonry. All the bents are braced together longitudinally at the top and floor-level of the bin by 8-inch channels and heavy i8o AMOMG THE MINES OF MEXICO n H angles : a* the ends of the bin the outward thrust upon the bents is taken by a truss-member at the top of the bin. The bents themselves are tied together at the top by -)4-inch plates 4 inches wide, riveted be- tween the channel-beams to the posts. Within this skeleton is a lining of plank, 4 inches thick in the bottom courses, with an inner sheathing of 2-inch plank having the grain vertical. The bin has a flat bottom supported on 4 by 14-inch joists on 12-inch centres, carried upon horizontal members of the steel bents before mentioned, on the top of which is laid a 3-inch plank covered by a 2-inch lining. The entire construction does credit to the manager, Mr. Carlos W. Van Law. While V e examined the mill, an interesting dis- cussion arose regarding the comparative value of the mechanical conveyor. Cars were advocated as econotu'cal because the cost of power alone (apart from repairs to the conveyor, maintenance, and in- terest on capital) exceeds the expenditure for labor when employing cars plus human labor. A conveyor requiring 7 h.p. at $7 per h.p. month is equivalent to, say, $50 or 100 pesos per month. The same work can be done by two peoncs at 50 centavos per day, equivalent to 30 pesos per month. In case a peon wears out, you can get another without absorption of capital! But alas for such calculations, the peon does not work on feast days. There is a great ad- vantage in employing machinery that goes forward without any stops. For in Mexico there are 25 fiestas THE MOTHER LODE J* per annum that are rigidly observed, besides Sum! ./ and San Lunas (or St. Monday— sacred to sober: ig observance), so that there are at least 75 days •{ interruption in a year, and wherever laborers are n- >t plentiful, this feature must be taken into recount. On the other hand, if one has a bin capable of holding a ten days' '.i p^ly of ore for the entire plant — as is the case at the Bustos mill — the bad effect of two or three days of fiesta is obviated. Of course, where a car-track is impracticable or where elevating is re- quired, the conveyor holds the field — and that is often. Leaving the Hacienda de Bustos, we rode up a ravine leading to the mines on the great lode of Guanajuato, called the Veta Madre, a term which in the guise of 'Mother Lode' has also been applied to the main vein-system of California. In the State of the Argonauts it refers to a general zone or belt sev- eral miles wide an-' ^"^ miles long, but at Guanajuato it defines a distinc : ar -hannel about 600 feet wide and seven miles kv .> he foot of the hill on which stands the 1 .v a<; iv- i e, the Veta Madre ■'. crossed by the Canoi ■:■ 7'.; '/te, and a natural scic of the big outcrop is visi»)U . The lode consist \i-it >. eight feet of silicified breccia; on the foot-w<"' > v posed in the bed of the stream, there is a quartz vein traversed by black streaks of argentite that dip at 45'; and under this ore comes brecciated schist cemented by quartz, the latter diminishing until the schist exhibits a ramification {ramillo) of stringers, . •fj ii ' mi 182 AMONG THE MINES OF MEXICO the dominant members of which are parallel to the foot-wall. Beyond this point, the quartz continues to decrease, and on the farther side of the stream the schist appears in the regular laminae to which it owes its name of hoja de libra, or book-leaves. This is the main foot-wall country. Remounting our horses, we returned down the caiion, soon reaching the Rayas church, a beautiful remnant of the loving architecture that the Spaniard lavished even on his mines. In these churches are found all sorts of queer pictures celebrating the thankfulness of the donor for deliverance from vari- ous perils. In them the miner testified to the danger of his calling, by the tribute offered to his particular saint. Ascending the hillside overlooking the church and its environing buildings, we turned to look on the crumbling walls of an old hacienda, which we had failed to notice as we rode past it. The walled en- closures seem inadequate for protection, and yet they served their purpose before long-range rifle practice was developed. Until about twenty-five years ago, brigandage was so rife in this, as in other parts, of Mexico, that the haciendas or reduction works were periodically 'held up' by outlaws, particularly in out- lying districts. As regards Guanajuato, their special nest was at El Capulin. on the road between Silao and Marfil. They terrorized the country, and despite oc- casional raids from the military, who drove them into the hills, the bandits would return after a short l^,i^^^^^ ■^ THE RAYAS SHAFT 183 ^md: interval, to resume their depredations. Finally, in 1883, the State Government sent a body of mounted police to attack them. Sixty men were captured, placed against a wall, and shot. El Capulin was completely destroyed ; not a hut was left to mark the spot. That ended the business. Passing close to the flying buttresses of the mag- nificent walls that enclose the San Miguel shaft of the Rayas mine, we entered the old enclosure. A sug- gestion of the appearance of this architectural sur- vival is presented by the photograph facing page 167. A little farther and we entered the courtyard of the Rayas shaft, one of the four great openings on the Veta Madre. This one is octagonal in shape, and 38 feet in diameter. The depth is 1,400 feet. Why these shafts were so big and the manner in which they were operated, will be told in the sequel. They make even the most self-confident American miner realize that his science did not begin at Virginia City, nor was it born in Colorado. The Rayas was sunk by the Spaniards in 1850, while the Valenciana shaft is a hundred years old, and yet one can read in the Mininff and Scientific Press of forty years ago that there was jubilation on the Comstock when the Ophir shaft reached 400 feet, and that doubts were entertained whether there would be machinery able to cope with any greater depth. Yet eventually the men of Ne- vada went down 3,250 feet. ■«■ l; -m Ml I ■ft n I (T^^ter 24 A GRAND VIEW— REMINDERS OF A FORJVIER TIME- ENGLISH ENTERPRISE. ROM the stone balcony or mirador of the Rayas mine, there is a splendid view of the country around Guanajuato. I shall try to describe it. In the distance to the left, the bold ridge of La Bufa, a scarp of rhyolite tuff, is sil- houetted against the clear blue sky. Under the o\'erhanging brows of these cliffs and protected from the weather, there are figures of heroic size painted on the rock: they represent a red devil and his retinue tempting the Christ. In the cavern adjoining these are several paintings of St. Ignacio and the Virgin, done i'i color with as much skill as the similar work to be seen in the churches. This mountain top — from which may be seen Guanajuato, Silao, Leon, ond the wide expanse of the rich Bajio — was supposed to suggest that from which El Salvador was shown the kingdoms of this world and their glory, in the great temptation. Lower down, near the talus slope, the ether temptations are depicted in a crude way. It is not said that the riches of the Vcta Madre were f I MEXICAN ARCHITECTURE I8S offered; they have tempted many men to their un- doing during the last two hundred years. On the rounded foothills that extend from the base of La Bufa begins the residence portion of Guanajuato; it is called La Presa, because of its dominant feature, a big dam with an encircling park. Seen from a distance, there is a gleam of pink walls among cedars ind the tops of some church-towers; then th€ crest of a ridge intervenes. At the foot of this and in the cafiada below the Rayas, there is a cluster of brown ruins, La Duran, the rildest hacienda de beneficio in Guanajuato, and contemporaneous with the discovery of the Patio process, in LS.S7. A hun- dred vards below it, the bed of the stream is crossed by the slender line of an aqueduct, which now serves to carry the pipe-line that brings the water-supply of the town. The six pillars are capped by a series of broad keystones, which do duty as arches. This is a characteristic typo of Mexican architecture." Be- low the aqueduct, the Canada turns to the right and becomes fringed by Peruvian pepper trees, and beyond them is the big hollow in which the town of Guana- juato lies huddled — a multitudinous complex of walls —pink, yellow, and white — with red Moorish cam- paniles. The narrow river-bed is marked by a con- "* The 'flat arch' is held by some to be the oldest and simplest expedient for supporting a structure ; it is supposed to h.ive originated from the big stone placed over a doorway in the days before the idea of the true arch was (levp:oped. Other engineers, for instance Mr Carlos Van Law, are of the opinion that the flat arch was a drvclopment from the true arch, and thnt, in form and principle, it is the roa! origin of our modem inven- tion' of fire-proof floor construction with its so-called arch-tiles. i86 AMONG THE MIXES OF MEXICO gestK "own walls; on the onlooking slopes the ;ase in the density of building and an inci . v-erdure, until the top of the ridges s reached, where there are no dwellings, but only the dark red earth of the cornfields, defined by hedges of organ cactus. Surrounding the town and o^'erlook- ing it, are golden brown hills, with contours deeply eroded and steep ravines, the culminating point being the cone of Cubilete. The broken sky-line is carved in diabase, and the nearer slopes are eroded in the con- glomerate that lies on the flanks of the main ridge. In front, beyond the huddled habitations of man and the brown hills, crossed by the traveling shadows of clouds that fleck the vivid blue of the sky, stretches the purple interval that marks the Bajio. a great valley along which runs the Mexican Central — an unromantic railroad, with slow trains, sloppy Chinese cooking, and a most distressing service. Beyond it, like the good things promised on the other side of this vale of tears, is the blue line of the Cordilleras, throb- bing with soft enchantment and pulsating with the romance of mining that shall not die. When luncheon was over we left the mir.idor, and in doing so passed through the remains of a pretty garden. It seemed strange to see the old-fashioned gilly-flower, rose bushes, and violets among these mine buildings. They had a story to tell of the Eng- lishmen who planted .them. There was a time, from 1824 to 1850, when English capital irrigated the min- ing camps of Mexico, and among them Guanajuato. ^gua- ^im 1»^A^ REMINDERS OF ANOTHER DAY 187 Owing to the costly methods of operation, the attempt to employ only the comparatively expensive imported white labor, and th*- lack of expent'nce in treating the silicious silver ores, these early efforts were generally unprofitable, although with their characteristic dogged determination, the English companies con- tinued to operate the mines, with steadily diminishing intensity, for many years. While aetive work on any important mine ceased fifty years ag^. they held on to the San Cayetano until within a few months, when that property was transferred by the Utt»ted Mexican Mines Association, Ltd., organ'.'.ed in ISU, to a new American company. Between the English period, already defined, and the present American dispensa- tion, there was a good dea' of work done under Mexi- can companies, although these lacked the t^nterprise of the heroic days at the very beginning of the nine- teenth century. (T^ter 25 iKau.i; THE GREAT SHAFTS OF THE VETA MADRE— THE RAYAS — THE CATA — THE TIRO GENERAL — WHAT BRYAN SAID OF IT-HOW IT WAS UNWATERED— A WONDERFUL SPECTACLE. HE four great shafts on the \'eta Madre are the Rayas, the Cata, and the two pits of the V'alenciana, namely, those of San Jose and Guadalupe. The Rayas is octagonal and 38 feet in diameter, with a depth of 1,400 feet. Among the old machinery to be seen near-by is a Cornish hoisting engine of 1835 built by Harvey & Co., at Hayle, Corn- wall; alongside are two Lancashire boilers. In an- other building is a first-motion hoist built by the Union Iron Works, of San Francisco, in 1866; it is one of the best of the old style, with jaw-braks and flat wire-ropes. The head-frame is built with timber struts footed in cemented masonry. This was erected in 1887, when the Rayas mine was unwatered. Rut there is a suggestion of methods used long before even this old machinery was set to work; the sites of the horse-whims used by the Mexicans is marked by a tablet inscribed to the patron saint of each operator. THE CATA SHAFT 189 One, for instance, reads "San Francisco. Nov. 1, 1820." The Cata shaft is 280 metres, or about 925 feet, deep and 20 feet wide. At the collar, and for 50 feet down, it is octagonal, with sides of masonry. I went down in a cage running on wire-rope guides, which gave one a feeling of detachment, for in places, below the portion that is lined with masonry, the pit is 30 to 40 feet wide. A native boy held a torch to illu- minate the distant sides of the shaft. The torch used in the mines is worth describing: It is called a mecha and consists of 40 native candles, made of tallow arid yarn, which are pounded into a mass and wrapped in a cloth with wood splints to stiffen it. Outside of this is a wrapping of riata or twine, obtained from the maguey plant. The torch is two feet long and 2>4 inches thick; it is wetted outside, so that the tallow will coneeal as it drips. By the light of it, when we reached the bottom of the shaft, we saw the Aldrich quintujJlex - -mp, made by the Allentown Rolling Mil'. V'ennsylvania. It consists of a battery of five vcr; . plungers, all the five cranks inside, with two post-bearings outside. This pump is said to be doing good work, lifting 300 gallons per minute to the drainage adit, 880 feet overhead. The San Jose shaft was also known as the tiro general or general shaft of the Valenciana ; it has been mentioned already in recounting the enrly history of (Kianajuato. It is an impressive hole. There is none like it. It is octagonal, ?3 feet in diameter and lined ■^ JJ^ g SLi - ^^- »M 190 AMONG THE MINES OF MEXICO with masonry for 100 feet. The bottom is at 525 metres or 1,730 feet. Water-level stood at 198 tretres or 650 feet at the time of my visit. This is the shaft of which it was truly said — among others, so I was informed, by Robert Bunsen at Leadville in 1881 — that a man can read his paper at the bottom by the light of the sun, because here in the tropics during the summer solstice the sun for two weeks is vertically overhead. Early in July, the mist caused by the sun's heat striking directly on tlie water at the bottom of the shaft, causes a beautiful rainbow every day at noon. This is the shaft also of which William Jennings Bryan — who visited Mexico after his first silver cam- paign and was royally entertained — said, that he had never before seen a hole big enough and deep enough to bury the gold standard. But he said nothing at all about the shallowness of the oratory of the river Platte! However deep the shaft may be, it will be filled up some day unless tourists are forbidden a near approach. From time out of mind it has been deemed great sport to throw stones down this vast pit and listen to the reverberations. I offered my tribute to the Tiro General. First one hears the sound of rushing wind — the echo of the passage of the stone through the air; then there comes a roar as it strikes the side of the shaft, and this is followed by a crash as it hits the water, (in the light of later events, here in San Francisco, I can te'l my friends at Guanajuato that these sounds resemble the on- 3 I HK (IkKAT Sn\hT (IK THK V.M.KNllANX, l.(H)KiN(: Down; thk. Sin Is KHKLECTto BV THE WaTKR at THE BoTTOM /■^^^^i£^.^m'L ;r^?Ais" "■' •■ r^iL-iW^ l«o Views of the Tiro General. Old Head-Frame, Boiler House, AND Chimneys miw- T^^'^^w: i 'f- ii 'i }. H ■^.Sll:. UNWATERING THE VALENCIANA 193 brought on ox-carts from Vera Cruz, a distance of fully 500 miles. A little farther north is the other great shaft, that of Guadalupe, which is 22 feet in diameter, and 325 metres, or 1,072 feet deep. It has a hexagonal collar built of masonry; through it a great deal of material was hoisted, the dump being the largest on the Veta Madre, containing 350,000 tons. The unwatering of the Valenciana shaft must have been a wonderful spectacle; the story of it is told in the old company's records. When they began, there were four steam-hoists raising as many iron buckets restrained by wire guides. The water being high in the shaft, it was not possible to anchor the guides to the bottom, so they were attached to a big wooden float, which was weighted until it sank. Then the upper ends of the guide-ropes were run over sheaves, in order that they might be paid out as the water was lowered. As long as only one hoist was running, all went finely ; but when all four got to work, the apparatus, that is, the float, guide-ropes, and toneles (bailing-buckets), commenced to twist until the whole lot of them were completely ^vound up in an utterly hopeless tangle. The bailing opera- tions had removed the water unequally over the area of the shaft, and this had created a vortex that caused the float to move round, twisting the 16 ropes used IS guides and the eight more employed in balance- hoisting, until with rapidly increasing gyrations, the .fe,.# IN till V- l '*■, ^f il l:iF • i V * I •i ^ i'i. »94 AMONG THE MINES OF MEX ) float became the base of a tangle that baffled descrip- tion and made the engineers hysterical. After the unwatering was completed, in 1881, Miguel Rul made a speech" before the Guanajuato Societ ■ of Engineers, and in that speech he dwelt upon their early troubles. The speech is on record. He describes the cylindrical iron bailers, made of gal- vanized sheets of No. 22 iron, with wooden bottoms and rawhide valves ; he tells of the various difficulties with the valve mechanism and over-winding, and then 1 e finally comes to the trouble connected with the attachmei t for the eight wire-guides below the sur- face of the water in the shaft. I quote his words: "On making the general trial with the four bolsters, after many partial trials which had resulted well, we noticed a phenomenon which disconcerted us. The effect of the different movements on the single timber- frame, to which the guides were attached below water-level, commenced to stir the water and to pro- duce a tumultuous motion of rotation, which finished by resembling a water-spout and winding up the cables and guides, completely interrupting the ma- ncBuvres. Many times we four engineers repeated the trial through a whole day, and the following day with only three (since he who recites this fell ill), withe it obtaining any favorable result. The three com- panions came to the bedside of the patient com- pletely disheartened and sad, as was to be expected, ,. , "T'''5 speech, before the Guanajuato Society of Engineers, was pub- lished m their Bulletin, and is dated August 5, 1888. •fe!i" EUREKA! J95 but at the same instant the same exclamation burst from the mouths of all, the very syllables falling to- gether, without anyone of the four being able to say, 'I was the first to speak'; we shouted, 'We will tecure the fixity of the frame with diagonal props resting against the walls of the shaffl This common idea was the equivalent of the Eureka! of the Greeks. It raised the patient from his bed, re-established happiness and, when put in operation, it gave the much desired re- su't. The ninth day of June, 1873, the unwaterii:g >vas inaugurated with great solemnity." What a scene it must have been; the courtyard fairly buzzing with the noise of the little hoists, the shouts of the bewildered engineers, the imprecations of the workmen, and the tremendous turmoil of the water in the big shaft as the guide-ropes twisted into a hopeless coil ! And then the silence when the whole came to a futile conclusion, the operations remain- ing suspended until those three mine captains, gath- ered around the bed of their invalided comrade, were suddenly inspired with the happy solution of their trouble. The courtyard is empty now, the waters have again invaded the shaft, and the vertical rays of sunlight once more pierce the gloom within the stagnant pit. (tfyxpYzr 26 li Ul :Ar THE MALACATE AND ITS OPERATION-THE AVIO SYSTEM-ELECTRIC POWER— A CURIOUS DIFFI- CULTY— HO^V THE EAGLES INTERRUPT THE CUR- RENT — A - RIKE. S a rule the miner does not choose the top of a hill for the site of his shaft; he goes where he can economize on his sink- ing, without depriving himself of the chance to distribute the waste rock. At Guanajuato the shafts are on knolls, some of which rise to the dignity of hills. The reason for this was the space the Spanish miners wanted for their malacates or horse-whims. At each shaft the re were so many of these that a yard of 100-foot rad'us was required. When this had been planned they - , . . ■ begin to construct a wall just beyond the end • arms of the malacute, the wall being built with the w. .. (extracted from the shaft), which was then filled 'nto the enclosure until the yard had a level surface. The haciendas were rarely near the mine, they were erected in the town, for the sake of safety and convenience. The ore was carried on mules to lue patio establish- ments, which were custom mills. I I,. "li' UA 1 I 1 r » ^ ■ ! ! t 't ■-.--. — — jL_: &_1 — I tl'* t f *ff Ir i i i'l. -■?1 ' a 1 i i ';f| 1 p [J 1 ^i 3 < ■;*fP^«ik'. '^ THE AVIO CONTRACTS 197 The mines were not worked by their owners but by parties who secured a lease in perpetuii_, termed an a'jio, which gave them (the aviadores) the right to do wiiat they pleased in the mine, and to make con- tracts for the disposal cf the ore. The aviadores charged, as a lien against the mine, all expense of whatever nature they incurred, such as development, operation, taxes, plant — in fact, everything. Against these items they credited the net returns obtained from the sale of ore, but being able to dispose of it wherever they pleased, they built haciendas on their own account and then made numerous contracts for the treatment of the ore, and mixed the several grades of it so that the yield could not meet the treatment charges. Then, as the owner never got a centavo unless there was a balance to credit, he never received anything. The mine ran up an ever-increasing debt until it amounted to an impossible sum; thus, for ex- ample, in the group of mines held by the Guanajuato Reduction & Mines Company, the indebtedness amounted to 6,000,000 pesos, most of this sum being entered against four properties, namely, the Rayas, Mellado, Cata, and Valenciana. The American company bought the avio contracts and the debt becomes payable to these new owners; the company inherits all the old contracts, including the agreement for ore-treatment- it will never have to pay the former — almost nebulous — owners unless the profits to the mine from sale of ore to reduction works first repay the accumulated interest and then grow r^ ii )'■ I I9t AMONG THE MINES OF MEXICO into a surplus. All the contracts are based on the old treatment charge, which was: 360 grams silver per ton to be deducted from contents of ore, the balance to be paid for at the rate of 3 centavos per gram; and the gold contents up to 6 grams per ton to be paid for at the rate of 30 centavos per gram; between 6 and 15 grams, the payment to be 45 centavos. As the aver- age ore of the best mines contains 350 to 400 grams silver and 3 grams gold, it is pretty obvious that the aviadores will not have to make an accounting. Several attempts, naturally, have been made to break these curious Spanish contracts, but in vain. The aviadores are the unquestioned owners of the mines today and no court can invalidate their peculiar rights. The new enterprises at Guanajuato have ^wal- lowed the avios, and all the big mines have passed out of the hands of the native population. It is a fact that the Mexicans look upon the American operations with scepticism, largely because earlier efforts made by for- eigners came to grief. They are inclined to regard with humor the removal of dumps and the working of abandoned mines; in consequence, although the old work was done by their own people, only a few local merchants have any financial interest in the present profitable undertakings. The introduction of electric power has been of great help in the re-opening of the old mines at Guanajuato. It used to cost 400 pesos per horse- power per annum, burning oak for fuel and using compound engines. Now the rate is five pesos per .^,..:Ak, {'—J ~jfT, A Bit of Old Mexico A Distant View ok GrAwirxTo HK V'll.I.AS OK THK I'kK^A k--^ INTRODUCTION OF ELECTRIC POWER 199 horse-power month for the right to use electricity, and 0.026 centavos per kilowatt-hour, the latter be- ing equal to about five pesos more per month if run- ning steadily, making the cost 10 pesos per h. p. month. The power comes from the falls of Zamora, on the Duero river, in the State of Michoacan and 101 miles from Guanajuato. There 45,000 to 60,000 volts are generated, with a step-down to 15,000 volts and again to 440 volts. Thus 4,0' '^' h.p. is generated, and another plant of equal capacity is about to be erected. Time flies. This must now be completed, for I speak of more than a year ago (November, 1905), when I visited Guanajuato. The natives were troublesome at first; they cut and stole several hundred metres of copper wire. Two men were killed by a live wire, after public warn- ing of the danger. There was also some difficulty at first in transmitting power, by reason of the sud- den change in temperature at dawn, when there is a rise of 15° C. This causes condensation of moisture on the porcelain insulators, which remain cool after the temperature of the surrounding air has risen. The moisture on the insulators is sufficient to cause the current to short-circuit between the iron pin of the insulator and the cross-arm of the iron tower. This happens between 5 and 6 a. m. The only way to stop it is to turn off the current, so that there is a break for an hour. However, energetic investigation into the subject will solve this difficulty, a return to wooden pins being possible. At first the break in 'il 7 1^1 200 AMONG THE MINES OF MEXICO transmission was attributed to the malice of d's- charged employees and then to the eagles, many of which were found dead at the base of the towers. They alight on the top of the iron supports at dawn and stretch their wings so as to arc across the wires, being killed instantly, but establishing a short-circuit through themselves before they drop. f^: ' ' I m^f 'if ] 4 ilf CbapUr27 THE PEREGRINA MINE— OLD SPANISH WORKINGS- SHRINES UNDERGROUND — ACETYLENE LAMPS — SAMPLING A DUMP. N the Peregrina mine, near Guanajuato, I had a good oppor- tunity of examining some typi- cal old Spanish-Mexican work- ings. We entered by a door into a small gallery and thence through the opening or mouth of the mine {boca de tnina) that descended into the darkness. The way was down a twisting stairway that zig-zagged within the vein- walls ; the steps were laid in lime mortar, the general slope varying between 45 and 56°. Such passages are common in the old Mexican mines ; they are made in stopes, the filling of which has been used to build the masonry of the stairway. At intervals, shrines are to be seen; there was one 30 feet from the en- trance, just at the end of daylight, and there was a principal shrine in a parapet above the big workings {obra grande) at the 100-ft. level. Every shrine is guarded by lighted candles, left there by the miners; and it is said that they will even go up and down the underground passages in the dark in order to save candles for this purpose. At about 5 o'clock, when i aoa AMONG THE MINES OF MEXICO the shifts change, t.iere are ISO to 200 candles burning before the principal shrine, forming a grand illumina- tion, the effect of which is heightened by the cavern- ous old stopes that yawn in front of the sacred image. As they pass it, the men stop and make a genuflection, with the sign of the cross. Descending farther, the stairway becomes wider as it passes into the big stope and we noticed another shrine — a toss set in a frame, with a solitary candle; this marks the spot where a man carrying drills {refaccthnero) tripped at the head of a series of steps and fell fatally. The big stope is a cavernous excavation 250 feet long, by 450 feet deep, and 8 to 25 feet wide. The footway at the end of the first stairs, about 100 feet from daylight, is blasted in the wall of the lode and is provided with a parapet of masonry. Leaning over it, one looks into an abyss, the efifect being like a miniature Cornice road underground. The lode is nearly vertical, changing from 80° W, at the south end of the mine, to a dip of 70° E, at the north end. The ore is from 8 to 20 feet wide ; it consists of quartz, partly ribboned and traversing a breccia, the edges of which show replacement ; it follows a line of frac- ture in the breccia; where the vein is tight and the quartz massive, the silver is highest in proportion to gold, ranging from 50 to 55%. Going south the lode becomes more open, the vugs contain clay, and there is such evidence of leaching as is usually seen close to the surface. In this part of the mine the proportion of silver to £,old is smaller. The Mexicans could not m 1 1= -Vv ^ 1 ^^ <' HB MF n Shrink in thk Pkhm^rina Mine II "!' fi f. :s ; I ■ i t ! i 'i I Hacienda San Francisco de Pastita Hit^^^BVh^^^^^m^ ■ .^d^^^^H^r ^HP^^' ' ^"^^ ^ !., *«-^. ■ — ^^ ! - ■^-. ^.:^:^^s.-/ r¥--:i!rr'!r- i li m^^^^^L^ :t.V -»«ff^ -..L^ ACETYLENE LAMPS ao3 work the gold ore because the haciendas paid nothing for gold and the ore- buyers gave only 30 centavos per grai , when it is really worth 66 cents or 132 centavos per gram. This ore cannot be sorted like that which is rich in silver, the argentite being visible in threads and spots, while the metallic gold is disseminated in particles too small to be seen. The argentite some- times impregnates the chalcedonic quartz so deli- cately as to make a moss agate. Our progress through the m:..e was lighted by two peoncs carrying mechas or torches. Mr. E. P. Ryan, the superintendent of the property, carrier' an acetylene lamp, so that the old and the new were well contrasted. The time may come when acetylene will be in general use underground, but it will not become popular until the present lamp is superseded by some- thing better. As it is now, you have a small can that holds the granulated calcium carbide and to this water is added; then the cover is securely replaced, and the chemical acti' n produces the acetylene gas, which is lit as it escapes through a small aperture. The smell of it gave me a headache, both in Mexico and in the Lake Superior copper mines, the two dis- tricts where I used acetylene lamps. But there is a newer invention that promises to prevent the escape of gas and the consequent headache. The emission of gas is nicely regulated and all of it is burnt in the process of illumination. We met boys (tanateros) carrying waste in tanates, the bags made of me fibre taken from the ixtle plant, 204 AMONG THE MINES OF MEXICO m 1 I II 'I tff a variety of maguey. We were passed by other natives descending to the place of their work, whistling as they went at a trot down the rough steps." Then, in contrast to such breathing antiquities, we found a couple of young mining engineers" who were taking samples in a thoroughly modern way, aided by Mexi- can miners to do the moiling. The quartz ore was hard and 10 to 15 feet wide, so that two moils were blunted for each foot of sampling. They used the straw hats of the barreteros to catch the sample. As we proceeded, I coiild see by the white channeling across the dark drifts that the work was being well done. Speaking of sampling, reminds me of the old dumps and the way they were tested. At the Pere- grina, this work was done by Mr. George A. Schroter. He did it with system and care. An aggregate of 250 feet of shaft-sinking was required; one shaft was as much as 70 feet deep, the usual depth being 40 feet. Each shaft was 3 by 4 feet in the clear; it was kept open by small timbers, 4 by 6 inches in cross-section. Two-inch round oak spiling was driven over a 'bridge' by double-hand hammers, as fast as the ground yielded, in consequence of the removal of the material at the bottom. The hoisting was done in baskets. The average cost was $1.25 for the first metre and then 25 cents extra for each succeeding metre of "A Comishman thinks it unlucky to whistle when underground. " G, A. Kennedy, of the Colorado School of Mines, and L. C. Pearce, of the Michigan College of Mines. I k ii V. n i ^! A Bin Stope in the Peregrina Mine 'a.4h kV_ (IT~~ 7*0^^^Kti. ^ 'A > 5 iii '■i^'d-^^Art'^'^. BUYING OF ORE ao5 sinking. The material obtained from each metre of shaft was kept separate and sorted, for .25 centavos per ton. This sorting was done by women, w ' > made three piles, consisting respectively of fine ore, lump (|uartz. and waste. On the day of my visit there were 60 to "0 women at work, handling 100 to 110 tons per day. They are better than men — more steady — because they do noi stop to smoke a ciga- rette; nor do they steal as much as their husbands and brothers. The sorting is done with a 3-lb. ham- mer, a horn spoon, and a wicker basket (ckiquikuite) reenforced with hide, holding about 30 pounds of ore. The dump contained $8 to $9 per ton, 70% of this assay-value being in gold. In the open-cut, where the ore is mixed with wall-rock, the assays averaged about $4.50 per ton. Underground, it was found that the filling of old stopes ranged between $b and $10, being highest in the southern part oi the mine, where the ore is more difficult to sort. The buying used to be done entirely at sight, the grade and weight were both guessed, with plentiful allowance for error and deception. The buscon or tributer would make a pile and put big chunks of good ore on the outside, and then fill his mouth with water and squirt it over the pile, so as to make a fine show- ing of black (silver) streaks across; the gray rock, on the same principle as the old woman polished the ap- ples for sale on her stall. n J\ w I ( ' f (i w ^1 i 1 1 - \ aSm W i ill h ■ I, f'M ! y ill M ^\^Ux 25 THE DUMPS OF GUANAJUATO— HOW TO SA vfPLE— THE MEXICAN IDEA — TWO TRUE STORIES — THE BITER BIT. HE dumps of Guanajuato have figured largely in recv^nt pros- pectuses, many companies hav- ing been organized with the par- ticular purpose of treating the ore left by the old Mexican man- agements. On careful inquiry, I can give the average assay- value of the best of these immense accumulations as 4 to 6 ounces of silver, and 1.5 grains of gold per ton, equivalent to, say, $4 per ton. When the American invasion began, the Mexi- can was not slow to appreciate his opportunity. In one case, peoncs were set to work removing the dump in sacks and lording burros with it, so as to impress a visitor with the idea that the stuflf was fairly rich. But grab samples gave only five ounces of silver per ton. It was hardly worth sacking! As regards sampling, in all the discussions on this subject while I was at Guanajuato, emphasis was laid upon the danger of doing the work without trust- worthy assistance. When using outside help, it is TLi, ILiaiiVliM'.'^P BiSKrvasii- NATIVE IDEAS OF SAMPLING 207 difficult to prevent salting, if well planned, unless the following three operations be performed: 1. Take samples with the help of the miners available. 2. Blast the lode at a few points and take check samples. 3. Cut down another set of samples yourself, with the aid of the one personal assistant, without whom such work should not be undertaken. Mexican miners make poor assistants to an en- gineer sampling a mine. When the groove is being cut across the vein, they linger in the rich ore from force of habit; it is hard to make them understand that the poor quartz must be included. To this very day, the Mexicans at Guanajuato deride the Ameri- can method of sampling. One of our friends had taken a large sample laboriously and carefully; he was just in time to see the foreman of the mine in the act of throwing out pieces of poor rock. "I'icne nada," "It carries nothing," he explained, as though it were foolish to include anything but rich ore. Other en- gineers can tell you of similr experiences, when, after breaking a sample with particular care to make it a true section of the vein, their Mexican helper has picked out the barren-looking quartz. The whole training of the native for generations has been to sort his ore ♦"ejecting the poor stuff, and he cannot get it into his head that anyone should do otherwise. But he is not the only eccentric ; when I was in West- ern Australia, during 1897, the owners of mining Sf ~S I H I ' II III f'lP^I' S.W.,', sri--- / r~l'"« [iC>.,.., i.»u r^jj,.!. IM.;, 21. some of which is ore, but the main orehody extends from the hanging into the agglomerate. The so- called 'foot-wall quartz' has been stoped on the fourth level for a width of 20 feet, and on the higher levels LIMITS OF PAY-ORE 219 this body o: poor quartz is 200 feet wide and there it lies aj^ainst the shale. The lode is broken by step- faults east of the Principe shaft, the fault-planes pitch- in,tr east at a strong angle. For a distance of 1,200 feet on the vein, northwestward from the Principe shaft, the lode is ore-bearing, to a varying extent, and in bodies of different shape. The pay-ore lies in soft iirccciated ground, exhibiting traces of oxidation and lying between the hard vein-quartz of the foot-wall and mineralized ground, the limit of which has not been determined. It is an imi regnation of irregular shape, extending along the structural lines of the ag- glomerate. At the time of my visit the ore as sent to the mill yielded 517 grams of silver and 2.76 gm. jjold per ton. The agglomerate does not wholly lose its identity by reason of impregnation with ore, and it is necessary to sample carefully in order to deter- mine where profitable exploitation will cease. It is fair to say that the cyanide process has done more to widen pay-ore than the geologist, that is to '^i% , che decrease in the cost of milling has enabled the man- ag^cr to treat profitably material previously considered too poor. Where the lode is not rich the distinction between quartzified country and profitable ore is de- termined by the assayer, and not by the mineralogist. The stalactites of iron on timbers and on the foot- wall of the old workings carry silver. As much as 30 grair.s, say, an ounce of silver, has been detected in such deposits formed within one year. The general assay-value is 5 to 20 grams per ton. After rains the 111 t^ 'I-, ,1; ! I. I I . V: U^i 220 AMONG THE MIXES OF MEXICO water of the mine contains 2>^ to 3% sulphuric acid and it will eat through an iron pipe %-inch thick within 60 days. I was informed that the orebody of the hanging wall, in the Sirena mine, was found while blasting for a cross-cut, intended to make room for a new hoist underground. The appearance of this ore suggests that it was formed by one of those movements that took place subsequent to the formation of the main fracture of the Veta Madre and its accompanying vein-matter; this later movement evidently shat- tered the older quartz-filling and then passed through the hanging-wall country so as to make a big mass of brecciated ground, suitable for infiltration by min- eral solutions, which re-cemented it with calcite and the more valuable metallic minerals. Diamond- drilling ought to be useful in exploring this ground; for the orebodies are large, but not connected. The old stairways and communicating passages appear often to be the bottom of underhand stopes, and therefore suggest the lower limit of profitable ore at the time the work was done. The accompanyint,^ photograph illustrates a part of the Veta Madre as seen in the Rayas mine. It is near the foot-wall, as indicated by the fragments of shale, which are partly silicified at the edges. Black threads of argentite traverse the white quartz. The geology of the Veta Madre has not received detailed study as yet, at least nothing has been pub- lished commensurate with the size of the subject, so i «l (» m l\ ''^ -n ' ■ 1 m ■ Jt 4 i 1; NOTES FROM HUMBOLDT 221 that Humboldt's observations still possess a com- manding interest. I shall quote from the old English translation already mentioned. He says: "The fa- mous vt.. .f Guanaxuato, which has alone, since the end of the sixteenth century, produced a mass of sil- ver equal to fourteen hundred millions of francs,'" crosses the southern slope of the Sierra de Santa Rosa." Beginning to touch upon geological matters, he states that "the most ancient rock known in the district is the clay slate {thonschiefer) which reposes on the granite rock of Zacatecas. It is of an ash-gray color and is frequently intersected by an infinity of small quartz veins. I consider this clay slate as a primitive formation, although the beds with very thin folia and which are surcharged with carbon, appear to approximate a transition clay slate. These beds {hoja de libra) are for the most part near the surface. On digging the great pit (tiro general) of Valenciana, they discovered banks of syenite or hornblende schist and .:ue serpentine, alternating with one another and forming subordinate beds in the clay slate." Humboldt wrote in French, so that his use of the term thonschiefer indicates that he was thinking of the Erzgebirge, at that time— just one hundred years ago — the most scientific mining centre in Europe. His description of the shale, which constitutes the foot-wall of the Veta Madre, is correct. It does ex- hibit a ramification of quartz veins. But the label • £57,754,620 or, say. $285,500,000. 222 AMONG THE MINES OF MEXICO n! 'primitive' will not do, for the formation is pr |y Cretaceous ; moreover, 'primitive' is a word be ng to an outworn idea, that the basement rocks were the origmal cooled crust of the earth. Petrography knows no simple starting point; the rocks we see are only m a particular stage out of the many through which they pass in the course of their geological evo- lution. The modern geologist begins with the old crystallines, earlier than fossils. The undermost rock now known is a granitic batholith, which seems in places to have invaded the oldest schists. This granite may be an original ign.-ous rock for aught we know. It IS probably not a fused sediment, and is the nearest approach to anything 'primitive.' The crystalline granite, formed by slow cooling from a molten magma, when exposed to weathering at the surface of the earth, becomes disintegrated into sand and clay which, being deposited in the ocean depths, are re- cemented and again solidified in ' rocess of time, pas<:- mg through chemical and physical changes that make sandstone out of the sand, and shale out of the clay, at first, and then by further interplay of subterranean pressure, heat, and chemical action, these become on the one hand quartzite, on the other slate, with a mixed product of schist between them. The Valenciana shaft passes through the car- bonaceous shale, with layers like the leaves of a book (hoja de libro) and penetrates the intrusive diorite, the decomposition of which, in places, gives the magne- sian rock that Humboldt called 'serpentine.' He con- '\mi 1 ^ja^maE^B^snisM^sssaKr?f!sm^ssj^^K'Tmm^KStT'-MM7^m^F?^ PORPHYRY AND FREE-STONE 223 tinues: "Porphyry forms gigantic stony masses which appear at a distance under the strangest aspect, fre- quently hke ruins of walls and bastions. In the coun try they go by the name of buffa. This porphyry, of which the Sierra de Santa Rosa is chiefly composed, IS generally of a greenish color." Colors in rocks have ceased to have the importance they once had for we have learned that the same rock can change its appearance while retaining an identitv of compo- sition. The name bufa still lingers at' Guanajuato (but It IS spelled with one f). and has almost replaced the higher sounding 'Sierra de Santa Rosa ' The sculptured summits and bold cliffs of La Bufa are due to unequal weathering of the rhyolite tuff that caps the Guanajuato series. Even in those days the term porphyry' played many parts. Continuing, Von Humboldt mentions that "on the southern slope of the Sierra, the clay slate is cov- ered with free-stone of very old formation. This free- stone {urfels-conglomcrat) is a breccia of clayey cement mixed with oxide of iron, in which are imbedded angulous fragments of quartz, lydian stone, syenite porphyry, and splintery hornstone." He speaks of the dip being opposed to that of the clay slate. Above this free-stone' there is "an agglomeration {lozero) of ater date from which the finest hewn stone is manu- factured. The free-stone is a fine-grained tuff, used in the building of the city of Guanajuato, as already men- tioned; It IS soft enough to be easily worked, and yet ' t4i:-:^'m^itS(.Mi>Ai. ; lI '' m z ■,», 2-4 AMONG THE MINES OF MEXICO hardens on weathering, so as to be durable. It is the cantcra of the Mexicans. This formation occurs both above the shale of the foot-wall country, as Humboldt states, and also on the hanging-wall side; in fact, it marks the extent of the great fault of 1,200 feet, along which the Veta Madre was made. On the hanging- wall side the dip of the country is nearly at right angles to the vein, which cuts strongly across the bedding, and, for a great distance, follows a line along which the later tufifs and breccia are opposed to the shale. But on the outer edges of the mining district, the vein cuts through the younger rocks also. Hum- boldt saw this; he says: "The vein traverses both the clay slate and porphyry. We have already stated that it has been wrought for a length of more than 12,000 metres ; and ye*: the enormous mass of silver which it has supplied for the last hundred years, sufficient of itself to produce a change in the price of commodities in Europe," has been extracted from that part of the vein alone contained between the pits of Esperanza and Santa Anita, an extent of less than 2,600 metres (8,529 ft.). In this part we find the mines of Valen- ciana, Cata, San Lorenzo, Animas, Mellado, Frau- stros, Rayas, and Santa Anita, which at different periods have been very highly celebrated." According to Humboldt, the European miners had been in doubt whether to consider the Veta Madre a "true vein" or a "metalliferous bed " An effect produced seventy years later, by the equally tremendous output from the Comstock lode, in Nevada. WHAT IS A TRUE VEIN ? 225 (crzlager)." He then proceeds to give some sound geo- logical views: "If we examine only the veta madre of Guanaxuato where the roof and the wall, in the mines of the Vclen- ciana or Rayas, are of clay slate, we might oe tempted to acquiesce -.1 the latter opinion; for far from cutting or crossing the strata of the rock, the vein has exactly the same direction and the same inclination as its strata; but can a metalliferous bed which has been formed at the same period as the whole mass of the mountain in which it is found, pass from a superior to an inferior rock, from porph)'ry to clay slate? If the veta madre was really a bed, we should not find angular fragments of its roof contained in its mass, as we generally observe on points where the roof is a slate charged with carbone, and the wall a talc slate. In a vein, the roof and the wall are deemed anterior to the formation of the crevice, and to the minerals which have successfully filled it; but a bed has un- doubtedly pre-existed to the strata of the rock which compose its roof. Hence we may discover in a bed fragment:^ of the wall, but never pieces detached from the roof." The attempts to define a 'true vein' have not ceased even a hundred years after the above words were written. While the debate is adjourned and re- sumed at intervals by savants, the miner has disre- garded evasive distinctions and has proved by his profitable toil that "metalliferous beds" are just about as good as the "true veins." The Calumet & Hecla, 226 AMONG THE MINES OF MEXICO I 5 li'Sl- the Leadville orebodies, the Aspen contacts, the ad- dle reefs of Bendigo and Broken Hill, the 1 nticular masses of Rio Tinto, the disseminated copper de- posits of Binghan: and Ely — to mention only a few — are representative of occurrences that do not belong I to what the schools of Saxony and Cornwall labeled 'true fissure veins.' Nevertheless, Humboldt's effort to distinguish betwen an ore deposit contempora- neous with the formation that encloses it, and one that has originated along later fractures crossing such rocks, is no* without interest. He refers to the in- clusion of rock fragments in the Veta Madre thus: "Its exte 1* varies like that of all the veins of Europe. When not ramified, it is generally from 12 to 15 metres in breadth; sometimes it is even strangled to the extent of half a metre; and it is for the most part found divided into three masses (cuerpos), separated either by banks of rock {caballos) or by parts of the gangue almost destitute of minerals. In the mine of Valenciana the Veta Madre has been found without ramification, and f >r a breadth of seven metres, from the surface of the ground to the depth of 170 metres. At this point it divides into three branches, and its extent, reckoning from the walls to the roof of the entire mass, is 50 and some- times even 60 metres. Of these three branches of the vein there is in general but one alone which is rich; and sometimes when all the three join and drag one another, as at Valenciana, near the pit of San Antonio, at a depth of 300 metres, the vein contains I J MEXICAN MINING TERMS M7 immense riches of an extent (puissance) of more than 25 metres. * * * Valenciana is almost the sole example of a mine, which for forty years has never yielded less to its proprietors than from two to three million of francs (£82,506 to £123,759) of annual profit." Here wc have the Spanish equivalent of our term 'horse' literally translated into caballo; it is the in- cluded rock that the vein rides, passing astride of it. If the branches of the vein do not re-unite, the result is a split or embranchment; if they come together, it is a 'horse.' Mexican mining terms are frequently dis- tinguished by their aptitude. The hanging wall is called alto (high or up), the foot-wall is bajo (down or low). But at El Oro I found that the natives spoke of the hanging as reliz (pronounced like re- lease). It is a word signifying a landslide or slip, and as suggesting a plane of parting or what a miner calls a '.shooting course,' it struck me as excellent. The hanging is also described as reliz arriba, or arriba by itself. Waste is lepclate. All stringers are called hilos, kilo being a thread. Ore that is speckled with black sulphide is known as mosceado, or fly-specked, mosca being a fly. At Guanajuato the honeycombed quartz on the foot-wall of the Feta Madre is termed chcrasco. Dikes of andesite penetrate the agglomerate and the shale in various directions, and, as Mr. Robert T. Hill suggests, it is to them that we may impute the 228 AMONG THE MINES OF MEXICO latest mineralization of the district; at least, it is probable that their intrusion along lines of fracture was coincident with a period of thermal activity. The Veta Madre, being essentially a big width of rock sheeted by fractures near the contact of two unlike formations, afforded unusually favorable con- ditions for the penetration of ore-forming solutions, which followed the main fractures and spread out- ward and upward into the shattered agglomerate, where they found the inducement to precipitate the wealth of silver that is now suggested by the name of Guanajuato. \i ' > ' • W i I I'M. ■ m M ui ■m^m*?^' TlIK i AN On thk Strket (ri)apUr 30 THE DEVFXOPMENT OF METALLURGICAL PRAC- TICE AT THE SIRENA MILL— FROM AMALGAMATION TO CYANIDATION— RE-GRINDING. T is worth while to tell the story n't the metallurgical develop- ment at the Sirena mill, more properly named La Hacienda San Francisco de Pastita. The suc- cessor to the old patio was a mill erected ir . ^^\ it contained 20 stamps, ». weighing 1,250 pounds. The ore was first broken by a 9 by 15-in, Blake crusher and was then reduced to 20 mesh by the stamps, from which it was passed to six Boss rapid-grinding pans. Here it was re-ground, so that all .-.ave 5 to 107'^ passed an 80-mesh screen; and then it descended to 12 more pans and six settlers. From these the pu!,) went to five Wilfley tables. The capacity of the mill was 1,500 to 1,800 tons per month. The product was amalgam and concentrate. The pans extracted 657c of the assay-value and the concentrate contained 127o more. This was on the oxidized ore. Although the concentrate con- tained two kilograms or 64.2 ounces of silver, it barely paid to send it to market under the smelter conditions then existing in that part of Mexico. 2y> AMONG THE MINES OF MEXICO im However, another factor came into play; as the lower workings were opened up, the percentage of recovery by amalgamation fell off until it was only 607c. Con- currently, the consumption of mercury and copper sulphate in the pans increased, while the concentrate became richer— 5 to 7 kg. silver per ton. The method was changed ; concentration was made to precede pan amalgamation. By this new arrangement, the cost of milling was reduced from 7.86 pesos to 4.81. The concentra- tion was carried further, so that the product con- tained 10 to 11 kg. silver and 115 gm. gold per ton; yet the weight of concentrate remained at 2 per cent of the crude ore. The higher recovery by concentra- tion balanced the lower yield by amalgamation, the commercial result being less satisfactory because the precious metals in the form of amalgam were worth more than when enclosed within a concentrate that had to be transported to a distant smelter. More- over, the variation in smelter rates introduced a factor of uncertainty. Extraction finally fell below 60%. This sug- gested an enlargement of the mill, so as to lower the fixed charges. At this period the Government tax and the expenses in connection with realization of bullion amounted to 11% of its gross value. The poor extraction and the high imposts left but a small margin of profit. A search for better metallurgical treatment was undertaken. The cyanidation tests made by Leonard Holms in 1901 did not seem to si '-'vm. A' ¥A-i'^^*i^ :^^^&::^}f^', .^. .. -^^ ' ^ . . 'i^mr^%- .. ■:; ' hk / . i ''^^1 \: |i^^H ii I 'ffl^l t ; I .,^9 j ^H ?! ■ -! ,1 H -3»?^a'^-*^W»- 234 AMONG THE MINES OF MEXICO K the slime and bringing the positive alkalinity up to \y2 pounds of lime per ton. Then this slime is pumped to the treatment-vats, the sand meanwhile going to collecting-vats, from which, after draining, it is taken in cars to the treatment-vats. This was the scheme at the commencement of cyanidation; subsequently, the masonry vats, for- merly employed in de-watering the pulp previous to pan amalgamation, were modified so as to serve for holding and thickening the slime. The five cone- classifiers were moved into the stamp-mill, in order not to lose 5^rade, and in this new position they de- livered direct into the masonry vats behind the old amalgamation pans, the vats built in the cyanide annex being used for the same purpose, namely, to de-water the slime. Even now it contains 70% water, and this 70% is just so much liquid that has to be displaced by the effective cyanide solution, until perfect diffusion is attained. The ore goes from the Sirena mine to the mill in cars (Kilburn & Jacobs) of 50 cu. ft. capacity, carrying 2.4 tons each. They have a double side- dump, with gable bottom, and appear to work easily. Waste is removed by sorting in the big courtyard at the entrance of the main adit. A sorting belt is to be used at the new Soledad shaft, the waste thus eliminated being returned into the mine as filling. The belt is to be 50 feet long, giving room for five men on each side, and it will be illuminated by shaded electric lights like a billiard table. Each man is to TCW^^^T'^W^WT ^a :tl HANDLING OF ORE 235 sit astride a wooden horse, which is high enough to giv freedom of reach over the belt. Gold can be seen in the surface ores of the Sirena mine; it accompanies the argentite. Pyrite does not appear to be indicative, nor is it a close associate of the precious metals; it is more plentiful in the un- digested country rock. In the ore of the Peregrina mine there is a little arsenical pyrite and also traces of antimonial silver minerals. At Guanajuato gen- erally, the average yield of concentrate does not ex- ceed two per cent, carrying 150 to 1,600 oz. silver, and from 1 to 30 oz. gold per ton, so that the problem is to treat a small quantity of high-grade material in competition with the excessive freight-charges of the railroads and the heavy treatment-rates of the smelters. Further, the Government tax is one per cent less on bullion than it is on the precious metals when in the form of concentrate. In September, 1905, the mill treated 3,887 tons of ore, containing 517 grams of silver and 2.76 grams of gold per ton. On leaving the concentrators the pulp assayed 302.5 gm. silver and 1.46 gm. gold. The concentrate recovered amounted to 106 tons, averaging 948.06 gm. silver and 46.92 gm. gold. The cost of crushing and concentration amounted to 1.75 pesos per ton. The extraction by concentration was 50.1% of the silver and 49.1% of the gold. The practice is still in course of developnicnt and experiments are continually being made. Re-grind- ing does not seem required by the Sirena ore; it is i I til .'i-^vi-^>i'^fy*. -V 236 AMONG TI^E MINES OF MEXICO stamped through ;. diagr^nal slot screen equivalent to 40 mesh; a cliuckbiock is used. Of the resulting pulp, 80% goes through 100 mesh. The granular quartz, when crushed, readily liberates the silver sulphide, but the chalcedonic gangue in which the silver occurs (in a cloudy dissemination like moss- agate) needs fine grinding — all of it — to pass at least 100 mesh. The concentrate carries 30% silica; the portion that passes through 200 mesh represents 15.5% by weight and as it is worth 398 pesos per ton, it contains 427c of the assay-value of the ore. In watching the agitation in the slime-vats, it was noticeable how the circular motion becomes ac- celerated until the moving mass of pulp and solution advances faster than the paddles. On starting the agitation, one can see the sinuous streaks of clear cyanide solution in the slime, and this condition of imperfect dispersion is never wholly overcome; it is due to the resistance of slime to diffusion. I noticed this appearance (or phenomenon) in a vat that had been at work for 40 minutes. Another note; even ten minutes after the agitator is stopped, the movement of water a top of the vat continues in the direction started by the paddles. Two pounds of lime are added per ton of solution in order to hasten settlement of the slime. The effects produced have been discussed in connection with milling at El Oro. The loss of sodium cyanide at the Sirena mill is 4.12 pounds per ton of crude ore, while the consump- tion of lime is at the rate of 6 pounds, worth 12 pesos ■iz-'^tev. ii^'fSmnf" I V I I M 2 } i.- [f • t. ? ' m "I -. - ^f ~ ^^^ «--.- • 1 fe-^ •^ ' ~ " r "^' ^ "^ Iv-i^ . . -' u O 3 Bl S H S < a 3 O to. O u a. S O TREATMENT IN THE VATS 237 per metric ton. Sodium cyanide costs I514 cents per pound delivered at Marfil station, the present terminus of the Mexican Central railroad; this price is on the basis of 100% cyanide, but as sodium cyanide contains 128 to 130% cyanide, the cost is actually a little over 19 cents per pound; to this must be added 1.25 pesos, cr, say, 60 cents per ton, for transport to the works, making the total cost about 19^ cents per pound. There is always some re-precipitation when treating silver sulphide, by reason of the formation of potassium sulphide, but this is diminished by the addition of lead acetate, which forms a plumbous hydrate that removes the soluble sulphides by form- ing a lead sulphide and the potassium or sodium hydrate. In practice, the re-precipitation of silver is surpassed by the re-dissolving of it in the cyanide solution. By passing through cone-clasjifiers the product escaping from the upper mill is divided into 'sand' and 'slime,' which are treated separately, or in the cyanide annex. In the 'sand' department there were 20 vats, each containing an average charge of 2,651.7 cu. ft., or 89.6 tons. During the month 1,792 tons (dry) 01 sand was treated. The average assay-value before treatment was 297.5 gm. silver and 1.37 gm. gold; after treatment the contents were 52 gm. silver and 0.1 gm. gold. In the 'slime' department there were 82 vats, each containing 3,851.8 cu. ft. of wet slime, equivalent to 24.26 tons dry. During the t I 238 AMONG THE MINES OF MEXICO 4:i: »i h' I ;1 / ,.. Vii i mo.uh, 1,989 tons were treated. The average assay- value before treatment was 275.5 gm. silver and 1.3 gm. gold. After treatment the assay became 45.5 gm. silver and 0.1 gm. gold. The extraction was 85.17c as regards the silver and 707" of the gold in the pulp treated by the cyanide annex, the total re- covery by cyanidation being 417 of the assay-value of the crude ore, so that the combined extraction by cyanidation and concentration was 91.2 per cent. The total cost of cyanidation was $4.13, and the consump- tion of cyanide 1.9 kg. per ton. Note should be made of the fact that successful experiments with cyanide on silver ore had been made earlier at the mines in Sinaloa, but the results had not been heralded because they were obtained at private properties, and even in these cases the official tests of the cyanide company at Mexico City had discouraged hope. The trouble was due to the use of too weak a solution — a swing of the pendulum in cyanide practice, for in its early .'i.s the main fault was the employment of a needlessly strong solution. Another factor that prevented success with these silver ores, was the insufficient time given for chemical action. The element cf time is especially important in the case of concentrate, that is. iron pyrite carrying gold free and silver as argentite; the millman can afford to give the time required because of the small quantity of this product and its richness. 'f;r m chapter 3t METHOD OF TREATMENT IN TI.-^. BUSTOS MILL- CONVEYING THE TAILING BY PIPE— THE STAMP- MILL— CYANIDE PRACTICE — COMPARISON WITH THE PATIO PROCESS. EFERENCE has been made to the milling practice of the Guanajuato Reduction & Mines Company in speaking of the Bustos plant. It deserves further consideration. Although the property was acquired in January, 1904, it was not until Februar>-, 1905, that it was decided to build 80 stamps, rushing the erection of five of them so as to afford experimental data during the construction period. Many tests, on a large as well as a small scale, had already demonstrated that a high extraction of both silver and gold could be obtained from the ore by cyanidation, and the experimental plant be- came of great service in testing ores from different parts of the company's properties, as well as to sug- gest the detail manipulation best adapted to the main plant, then under construction. The mines are a mile from Guanajuato, and there are no streams avnilable for disposing of the tailing; nor is there the • i-ce necessary for accumulating residue on a large [< 340 AMONG THE MINES OF MEXICO t- 4 scale. It became necessary to discharge the i Hng into the main stream of the di'^trict one mile fro' i the mines, and this mean' the transport of all ores through the heart of the Cit\ over an expensive rail- road system, or the com Ictc scpanition of the stamp- mill from the cyanide plant, the latter to he placed upon the main strcai. The Homestaki system, < . conveying iSie tailinj:^ in a cast-iron sevvc pipe, was adopted; it i an 8-i i. vater-pipe of bell ..nd spigot type, asphalted, laid for Its first few hundnd feet at a grade of 5%, then fla! tcning to 2]/^^%. As it was desirable t ■ sett'c am! return for re-use as much of the water cming fron the concentrators as possible, allowing tht thii ; ilp only to pass through the pipe, and to det rnune to what poin^ st'ch thickening was possible, S( ral hun- dred feet oi the pipe to be employed in this crk w - put together and laid on* upon the actual graue. Arrangem* ntv were mm! to circuit any rnen (iuaiitity (■ ami (crushed in the stamps tli "x ffi- iii ntal plain already installed) through lin- , -line at my desired degree of dilution. Pul[ w. first tried at a -rmal dilution of 8 i.t water t( 1 of sane just as it cani'. from the tail )f the concentrate fables; the water wa-^ then d inted by successive strps, thickening the p-f -p, an , ' ri. were made under the-e vary- g cox\<' on.>. Tt v de- sired to remove a maxim nof< alf le ( jinal water, and in the expersn ents tne -^ to 1 j dp \v.. ^ re- duced to 2.5 to 1; and o success ally thai not o' H' CUXMiYING TAILING THROUGi PIPE 241 cr '^i- of ! pulf ar ■ was ihe pipe not clogged with san«l, but the pulp at tint thickness had such rapi ity of flow that it readily lined r^st-iron nuts and othei iieavy objects with- u; interrupting 'he strear T si. made by Mr. I arid- Van Law irove tiiat pulp which has passed tt ouirh a 30-mesl screen, with water in the propor- ii n < 7'/2 to I, v.. li fl( w throuf h a launder of square tior made of rough boards, set on a grade \\ ih ^ V-shaped wooden launder, such !' ow at ' 'ss grade aid with ess water. The •H erimcter is thechii ictor. pr n sett d, the proce as outlined as is nsported ov- i railroad from he mi^* jppe ttom cars, vhich discharge ' a ,c bin at tl, rusher plant. It is then re- -ci! a No. 5 D. dates crusher to 2-in. size, dis- arging over a picking-belt for moval of waste, •hen re-crushed by a short-head N( 1-in. ring, then removed by cor mill-bins, where ii is distribute to cheap labor) proving mor- use of a system of conveyor-beii b with automatic trippers. Tlu c icity for five days, which, togetl bi- at the crusher plant, affords sutticiem storage of ore. The ore is then crushed under eighty 1,050-lb. stamps of AUis-Chalmers make. The mortars are set on a concrete f'.;.ndation, the anvil-block being cast as an integral pave of the mortar. The latter has a 4 Gates crusher yor-belts to the ars, this (owing ical than the *:he top of a !-bin has a h the large [i 242 AMONG THE MINES OF MEXICO Steel liner, two inches thick, but there is 13.5 inches of metal below the liner. Between the anvil-block and the concrete a quarter-inch sheet of rubber is spread. The mortar has a broad base— 36 inches wide— provided with strong ribs at the sides. The 30-mesh pulp resulting from the stamping is concentrated over Wilfley tables, a considerable amount of middling produced being removed for re- grinding in an Abbe tube-mill and subsequent treat- ment over separate concentrator tables. The tailing from all the machines drops into concrete launders and passes to the cones, where about half of the water IS removed for use in the mill. The thickened tailing then enters an 8-inch cast-iron pipe, laid with the gradient above mentioned, and goes to the classifiers in the Hacienda Flores, situated upon the main chan- nel of the Guanajuato river. The classifiers are all of the Homestake type, two sets of cones being used, the lower one taking the bottom product of the upper The overflow from both sets of cones goes to the slime plant, the lower cone having an ascending current of water. The sand coming from the bottom of the lower cones IS distributed, by the Butters & Mein device, into either of two receiving-vats, each of 350 tons capacity. These were planned to serve an ultimate capacity of 500 tons daily, with the slime separated. The receiving-vats are alternately filled and drained, the discharge being made through bottom gates onto ascending conveyor-belts, which pass over PiPK-LiNE FOR Conveying Ta TlBE-MlLL AT PaCHUCA 'i' ^ at - U ^«ii^<^^jij; THE HACIENDA FLORES 343 the centre of the line of eight leaching-vats, each of the same size as the receiving-vats. In these a 14-day treatment is given with 0.5% cyanide solution, the sand being then washed and ultimately discharged on conveyor-belts (running under the vats), which deliver either into the river during the rainy season, or to elevated storage-piles during the dry season, to be sluiced during the succeeding rainy season. The slime from the classifying cones is treated by agitation with mechanical stirring and large cen- trifugal pumps, which draw from the bottoms of the vats and discharge over the tops, the total time of treatment being four days. After the final wash the slime is pumped into settling-vats 30 feet high, where a further decantation occurs before the slime is dis- charged, with a very small percentage of moisture, into the river. The entire plant, both the stamp-mill and cya- nide annex, is designed so that it can be doubled, when the stamp-mill will take a back-to-back form, 80 stamps with their concentrators being on either side of the bins. The classifying-cones and the receiving- vats of the cyanide annex are of sufficient size already for a 500-ton plant, it being necessary only to add another line of eight leaching-vats and the corre- sponding slime-vats to bring the cyanide plant to the larger capacity mentioned. For roofing, corrugated galvanized iron on a steel frame is preferred. As there is no load of snow to fear, it is possible to use a light roof-truss. The 1 i^^^^^H ^5 :j^aMaHK ^]^^E '^^^^^■^^B jflVi ^^^^^^^^B I^P ^^^^^^E ■ i^H 244 AMONG THE MINES OF MEXICO H'-f* i! native tile is cheaper, but it requires a heavier con- struction, and does not afford as complete protection. The Northerner will remark the lavishness of the masonry about the mines and mills in Mexico. It is the cheapest kind of construction and the native wood is usually poor; it will twist and untwist as the dry and wet seasons succeed each other, making it an unsatisfactory structural material. At the time of my visit there were 120 stamps in operation in the Guanajuato district, and there were 205 tons being treated daily by cyanidation and 25 to 30 tons by the Patio process. Thus does the new drive out the old. In 1887 there were 34 pattos at work ; now there are only two. In regard to cost in the Patio process, I have the following data from the Hacienda de San Julio at Pachuca : Pesos. Crushing, to pass 60-mesh in Chilean mills, with overflow discharge. . 3.60 Maintenance 0,50 Salt. 5%, or 50 kg. per ton 1.7S Copper sulphate. Loss, 0.5% " " " l'2S Mercury. Loss, V/, kg. for each kilogram >•'. silver 4.X Transport from the mine 1.O8 Total i^ The ore is bought on the dump, therefore the cost of transport is included. Salt costs 35 pesos per ton; copper sulphate, 250 pesos per ton; and mercury, 3.41 pesos per kilogram. The average losses for the year were 1.18 to 1.50 kg. per kilogram of silver extracted; the loss of silver being 6.13 to 10.92% on the clean ore, and 15.83 to 29.13% on the galena ore. The Patio '^1«*£b-^ THE COST OF THE PATIO PROCESS 245 process waits on the completion of the chemical re- actions, and it is therefore continued until extraction ceases. Time is not considered; in winter it requires 20% longer by reason of the lower temperature of the air. At Parral, in Chihuahua, with the Russell process, usmg hyposulphite, the cost of lixiviation and roasting is 11 pesos, but the recovery is not as high as It is with amalgamation on the patio, where the cost IS 11 to 14 pesos, varying according to the manganese content of the ore. At Pachuca, by Mexican methods, the cost of mining and sorting ore amounts to 15 pesos per ton- the transport to the patio and the treatment there add a further expense of 14 pesos, not including losses or the expense of marketing the product. By stamp- milling, pan amalgamation, and concentration, the cost at Guanajuato was 8 pesos; and now by stamp- milliiig and cyanidation the cost is 5.85 pesos. That of mining and development is 3.50 to 4.50 pesos, so that the total present cost is about 10 pesos, or $5 per ton. At the time of my visit there were about 200 men women, and children in the Anglo-American colony at Guanajuato, the American element predominat- ing. Of the 125 men employed, 75 to 80 were techni- cal men, of good training. This made a strong piece of mental machinery for industrial development. C\)afUr 32 OLD METHODS— AN ABANDONED ARRASTRE— THE HACIENDA DE ROCHA— MEN AND MULES. ^f;:^' XAMPLES of old methods of engineering, now becoming dis- placed by the aggressive inroads of technical science, are afforded by two photographs that are re- produced on the accompanying pages. One shows a Mexican drawing water by the aid of a mule operating a lantern-gear wheel. In the fore- ground is a channel, made of cement, along which the water is directed for purposes of irrigation. The adobe walls and pepper tree (perul) are typical of Mexico. In front of the well there are two women, one Oi whom is washing and the other gossiping. It was ever thus. On another page there is a photograph of some old machinery at San Francisco, in the State of Michoacan, and about seven miles from El Oro. In the foreground is the pit of an arrastre; the cords that attached the mullers or grinding stones to the re- volving arms of the machine are easily distinguish- able. The cord or riata is made of grass fibre, although for this purpose leather thongs are more usual. Motive power was obtained through the wooden spur-gear operated by a water-wheel within H"1 \ n !) iti 1 1 i 1 Pii li(' j 1' (li mn't ihf\ ■ i i I f if 11 1 • .1 '1 An Oi.I' , Rxs ^•Siicfflk. .,ym3i AN OLD PATIO ^^ the building, the wall of which forms the background. The water-wheel is 20 feet in diameter and carries a pm.on that gears with the crown-wheel on the ver- tical shaft of the arrastre. One of the discarded (be- cause worn out) grinding stones lies in the sunlit foreground. As the Patio process is surely destined to become obsolete with the introduction of more rapid (and therefore cheaper) methods of metallurgical treat- ment, It ,s worth while to preserve an accurate record of this old method of extracting silver from the ore By courtesy of Mr. Bernard MacDonald, I am able •"^ ^^^t'V^r^ P^^*" accompanying a report made in 1866 by E. T.Ilmann. the Royal Commissioner of Zl. I" ^'"''''" ^^^'^ h^^ ^'^'t^d Guanajuato m 1865 at the instance of his own government to ex- amine the mining practice then obtaining in the most progressive parts of Mexico. The plate opposite page 250 gives a photographic view of the Hacienda de Rocha and a plan of the es- tablishment, the various departments of which are mdicated by letters, with an explanation in Spanish on the margin. This is a good example of an old haaenda de beneficio, the mechanical details being illus- trated in five spirited drawings, all of which are here reproduced. Fig. 23 shows the stamp-mill, with wooden stems (*. b) shod with iron (r, c), resembling those generally used in Mexico until recently. The motive power is obtained from four mules harnessed iVS!f-^S9l?SSI^B&M' '^ "SZf if'j I, I I r \r \^ 248 AMOXG THE MIXES OF MEXICO 'i;i \l r;"'-* F^ '?' H M ^ 4 % 1 i _ ^^sii^:^ ^^r OLD METHODS 249 Fic. 25. .Ji jij|;'ii';'*fe' m'i -i-ii^i^ ', I! 350 AMONG THE MINES OF MEXICO I : Vt to the long arm (k) of a whim or malacate. The teeth of the interlocking wheels are made of wood. After being crushed under the stamps, the ore is passed to the arrastre exhibited in Fig. 24. Here the fine grinding was done. The mules are again in evi- dence. The bed of the arrastre consists of stones placed on end and the muller or upper grindstone (/) is hung by chains {g) or leather thongs from the radial arm {e) extending from the pivotal axis {a). When it had been reduced to a fine pulp by the arrastre, the ore was allowed to settle and thicken before being taken to the open yard or patio where it was mixed with magistral, salt, and quicksilver, as we have seen at Pachuca. After being exposed to the air and thor- oughly mixed by the tread of squads of mules, it was conveyed to the settling-vats shown in Fig. 25, where it was thinned with water, so as to allow the amalgam to separate and accumulate on the bottom. Then the amalgam was distilled in an iron retort of the shape indicated by Fig. 26. This resembles the one .s -n in the Hacienda La Union, at Pachuca, and described on a preceding page. Finally, in the last drawing (Fig. 27) there is an excellent rcpresentati. n of the manner in which the cast-iron hood was raised when the distillation of the mercury was completed, dis- closing the sponge of silver that remained in the re- tort. This silver was melted into bars. "By the wayside of progress lie the broken images of the past." |ii i mmm ') .(1 Vi o z 9 , l. RETORTING THE AMALGAM 251 1 ^1 ^^^^B' ^^^^^^^^B ilB'' Fig. 27. I I C^KipUr 33 THE FLOOD AT GUANAJUATO— THE HUMOR AND THE TRAGEDY OF IT— CONCLUSION. Hi l», ♦■■ H UANAJUATO had a flood, and like that of Noah, it serves as a new starting point in local his- tory; things happened B. F. or A. F. The catastrophe occurred on the first and second days of July, 1905, so that the recollec- tions of it were still vivid at the time of my visit. Unusual tropical showers poured upon the neighboring country, and the waters con- verged from a steep watershed into a narrow ravine choked by bridges and crowded with dwellings. Never wide, the bed of the Guanajuato river had been elbowed by roads, houses, and debris, so that in places there was left a channel only two metres deep and four metres wide. Furthermore, it was ex- tremely tortuous, the original course of the river having been repeatedly diverted to secure space for buildings. On the first day, the water rose to a level which just exceeded that of the flood of 1873— about four feet above the street. On the second day th-^ volume of water doubled, it rose 15 to 17 feet above the pavement, and made terrific havoc among the soft masonry and mud walls of the old town, which melted like salt before the onrush. A few THE FLOOD 2S3 minutes sufficed to cause the collapse of many build- ings, and to create fearful confusion. At that time a sewer was being constructed at the upper end of the town, near the Presa, and the timbers of this were torn out, to be carried forward so as to form a batter- ing ram, demolishing the adobe walls and choking the confined channel of the torrent. Officially it is stated that 54 were killed, but 73 were carried to the morgue, and it is probable that fully 100 people per- ished. Many Mexicans from the outside country happened to be visiting the town, it being the time of a fies/j, and of these a number were never accounted for. No Europeans or Americans were drowned. At the time, there was nothing humorous about the disaster, but,' with that happy instinct of hu- manity, as the horror was forgotten, some of the ab- surdities were remembered. To the natives it was an opportunity for spoil; looting was general. "Es un Tcgalito de Dios a nosotros que no sabemos trabajar —"it is a little gift from God to those of us who don't know how to work," so they said to themselves. Some of the peones laid their hands on a shoe-store that had been devastated, and to this day they can be seen wearing a tan shoe on one foot and black leather on the other. The pink and green steamer-trunks of an American lady glorified the torrent for a while- they bobbed under the arch of a picturesque bridge,' and Ian -led in the second story of a needy native. A mule was borne by the flood into another second story, and in his terror he bit into a box of Ivory soap, >4i (■•^ i i 254 AMONG THE MINES OF MEXICO and it was this that buoyed him across the waters. Billiard tables, with their slate rops cruelly exposed, were engulfed in the whirling debris. Seventeen pianos and two cannons meandered down stream to the sound of many waters and their own spontaneous accompaniment. An azure splendor suffused tiie scene as a box of bluing irom a laundry made its vivid passage; whereupon the pianos played a fa- miliar waltz of Strauss. Bolts of silk appeared among late mules and defunct pigs, street-carp were seen with men balancing on their unsteady decks until the upper windows of a church offered shelter. The Teatro de Juarez received a complement of burros, and the compliment of their lamentations, which simulated grand opera, ju'^t as the sequel imitated Noah's Ark, for when the waters subsided, they made their timid descent down the grand staircase with alt the dignity befitting a momentous occasion. But worse things than these happened ; a case of Saratoga whisky floated onto the desk of a total abstainer — and the owner of the whisky never saw it again. With the downpour of rain came darkness, tiM natives lit candles, and the women came o«t on th« balconies with lights, wherewith they made the s^ of the cross, the church bells were rung, and to the natural horror of the scene was added a touch of solemnity. This was on the first day; when the sec- ond flood came in the late afternoon of the second day, with its repetition uf an uncanny darkness, the people crowded to the adjoining hilltops, which y^8yg!r»'Sf«RJggg'« .il!, i BUJU-JLIU i lliiL i ijllll .^^^im'* '— .-■.i««t-i-r*i«r» fill. f li , I CONCLUSION 255 were brilliantly illuminated with moving candles, while the air vibrated to a thousand bells. To them it was the end of the world, and we, of San Francisco, who saw a greater devastation, can well imagine that to their simple minds it seemed a horror beyond explanation. And so I come to the end of the notes that record my recent travels in Mexico. To speak in the lan- guage of photography: I brought some films from Mexico; most of them were only snapshots, there be- ing no opportunity to get time exposures ; therefore the images that I have delineated, and the impres- sions that I have tried to convey, may lack definition. But beyond the mental imprints which it has been my endeavor to transfer to the pages devoted to this account of a journey in the southern land, I brought other memories and experiences, which were never developed ; they remain blurred, and to none but my- self have they a meaning. I have recollections of multi- jlored facades, of sunlit walls, and cool patios, the sound of bells, and the cracking of whips, cries of cervcza and frijoles, conical hats and hooded women, a stream of chocolate-colored humanity, a politeness that gave dignity to the commonplace, a squalor that soiled romance, and a sunshine that glorified every- thing; and then, like the refrain of a song that we love, the kindness of the men of my oWn race, and the hospitality of women who make every abiding place a home. And so, Vjyan con Dios ma amigos. V i I 1 'U "Across t()e San 3uan Mlountalns Being the account of a ride over the mounuinou* mining region, of Southwestern Colorado, in September. 1902. Reprinte-i by per-ni„ion from I he Engineering and Mining Journal it .1 I .3 ' 1 ^^^V^^^^Te. I ■A.l. , I i ii |.i k s^. i f ii: ConUnti (rhapter _ Page I. The Start from Ouray. Visit to the American Nettie Mine. Clastic Dikes. A Picturesque Tramway i a. The Bachelor Mine. Trail Horses and MounUin Transport. Miners' Cottee. A Strange Dike. The Theory of Its Formation. Description of the Bachelor Lode 3. Across the Range to Telluride. Mountain " Roads. The Camp Bird Mill. Treatment of the Ore. The Local Geology. Electrical Power . 20 4- The Camp Bird Mine. .Story of Its Discovery by Thomas F. Walsh. On the Top of the Range. Arrival at Telluride 28 5. Mills and Tramways of Telluride. Operations at a High Altitude. Snowslides and Their Effects -2 6. Destruction of the Camp Bird Mill. The Assassina- tion of Arthur Collins. Labor Riots . . 38 7. The Smuggler-Union Mine. Structure of the Lode o ^ Geological Conditions. Variety of Minerals . 44 8. nie Contention Mine. An Aerial Voyage. Good Mine Management 9. On the Way to Silverton. The Bridal Veil Falls. Fine Geological Section. Ophir. The Red Mountains 10. Silverton and Its Early History.' The First Smelters in Colorado. Pioneers of Industry. Rapidity of Development f- 11. The North Star and Silver Lake Tramways.' Some Uever Engineering. Comparisons. Double and Single Ropeways. Eureka. Veteran Miners. . 66 lit MICROCOPY RESOLUTION TEST CHART ANSI ond ISO TEST CHART No 2 1.0 I.I i ;f iiM t 1^ ill 2£ 1.25 jjiiju 1.8 APPLIED IK/MGE Inc Rorhesler, Nc» Tork '4609 jSA I 7 'ft) *«;■ nlOO - Phon# CONTENTS M / \ * «! If • R' Chapter 12. The Page IS- M- IS- i6. i8. 19. 20. 21. Cinnamon Pass. Electrical Transmission of Power. The Tabasco Mill. Burroughs Park. The Secondary Enrichment of Copper Veins. . 75 The Golden Fleece. A Bonanza and Its Vicissitudes. Geological Features. Theories of Lode Forma- tion. The Treatment of the Ore 80 Slumgullion Gulch. Landslides. The Cannibal Pla- teau A Grim Tale. Rock Disintegration. A Natural Cathednii 87 The CeboUa Hot Springs. Thermal AcMvity in the Rocky Mountains. Its Relation to Ore Deposits. Th'- Gunnison Plateau 92 Vulcan. The Good Hope Mine. Geology of the Vein. Native Sulphur and Tellurium. Acid Waters. Theories of Origin. Rare Minerals . 95 Gunnison. The Derelict of a Boom. Crested Butte. The Irwin District. Silver Vein in Sandstone. Anthracite. The Smith Mine 105 The Coal Mine at Floresta. How Anthracite Is Formed. Methods of Mining. The Breaker. A Panoramic View '12 Over the Ohio Pass. At Gunnison Again. Fishy Yarns. Gate View. Poetry and Geology . .119 Lake City. The Ute and Ulay Mines. Concentrat- ing Mill. Electrical Drills. New Mills . . 123 Rose's Cabin. Climbing the Range. A Snowstorm. Bear Creek. After the Storm. A Glorious Pic- ture. Arrival at Ouray 127 n ■■ '■ ! '( 1 ' ■ IV TCul of HUuslraUons Facing Page The Amphitheatre of Ouray 4 The American Nettie Mine, near Ouray 5 Pack-Train at the American Nettie Mine 6 Mules Laden with Lumber for the Mines 7 Pieces of the Qastic Dike in the Bachelor Mine . . . . lo A Prospector and His Burros H Sunshine and Shadow on Snow. The Silver King Mine . I2 The Camp Bird Mine I3 In the Heart of the Mountains i8 Mt. Potosi 19 Mt. Abram, near Ouray. A Bit of Geology on the Road-Side 24 Hauling Concentrate from the Camp Bird Mill .... 24 The Revenue Mills, near Ouray 25 The Crest of the Range and the Upper Workings of the \ --ginius Mine 25 Mt. \\ ilson and the Valley of the San Miguel 3° Savage Ba;in 3^ The Liberty Bell Mine 36 The Bullion Adit of the Smuggler-Union Mine .... 37 Looking down Canyon Creek 38 Camp Bird Mill Burning 39 Destruction of the Camp Bird Mill Ly Snowslide and Fire . 42 After the Fire at the Camp Bird Mill 43 The Smuggler-Union Mills at Pandora 44 The Smuggler-Union Mill at Pandora 45 Smuggler-Unluu Tramway. A Load of Lumber .... 52 Marshall Basin 53 Looking Backward from the Bridal Veil Trail ... 54 Telluride and Its Geological Section 55 V } "'I ■I ft ^: l.i. ! I ! '<-.S W LIST OF ILLUSTRATIONS Facing Page Timber-Line. At ii,ooo ft. above Sea-Level 58 The Ophir Loop. The Village of Ophir in the Valley Beyond 59 Silverton 60 The Mines of Red Mountain 61 Breaking Trail Through the Snow. 'Man in the Bucket.' An Easier Mode of Travel 68 Rope Tramways 69 A Pack-Train on the Way to the Old Hundred Mine, in Cunningham Gulch, near Silverton 76 The First Snow. Silver Lake Trail 77 The Toll Road between Ou.uy and Silverton 82 The Valley of the Uncompahgre 83 Yellow Mountain. Early Snow 94 Vulcan. Burroughs Park 95 Diorite Contact on Silver Mountain, near Ophir . . . .102 Looking Down the Valley below Red Mountain .... 103 Mt. Teocalli. A Highland Meadow 106 After Riding 400 Miles 107 The Portals of the River i" Mt. Sneffels "3 After the Storm. On the Crest of the Range 128 Ouray 129 VI a TLlsl of T)rawln3s Figure Page Map of Southwestern Colorado 3 1. Pockets of Ore 4 2. The Bachelor Dike 11 3. A Cross-Section 13 4. A Disappearing Fault 15 Section of American Nettie Orebodies 18 Dike of Gilsonite 19 5. Section Along Uncompahgre Creek 25 Map of Telluride District, Colorado 27 6. The Smuggler Vein 46 7. Another Section of the Smuggler Vein .... 47 Cross-Section of the Contention Lode 50 A Fault- Vein Faulted 54 8. Section Along the Golden Fleece Lode .... 82 A Lode in Quartz-Schist. Mew Zealand .... 94 9. The Good Hope Vein 97 10 and II. Examples of Vein Structure 99 12. The Ruby Chief Vein 109 Upturned Strata of the West Slope of the Elk Mountains iii 13. Porphyrite Dike in Sandstone 115 Geological Map of the Anthracite Region . .116 The Laccolith of Mt. Marcellina 118 Gothic Mountain. A Trachytic Mass Overlying Cretaceous Rocks 122 vu li. -1 ytl-'i ^t''t < i * 1 . .1, ':' •'' '1 1 11 II \ ! !'^!: f a mi \i ik ,1K "l^cross tl>ft San ISuan 2^ountaiR5 (Li)aphr X THE START FROM OURAY— VISIT TO THE AMERI- CAN NETTIE MINE— CLASTIC DIKES— A PICTUR- ESQUE TRAMWAY. N a superb morning in September, that month of many colors, four of us' started on a ride among the mining districts of the San Juan in southwestern Colorado. The starting point was Ouray, the pic- turesque little town named after the old chief, an In- dian of renown, the friend of the white men that first explored the mountain fastnesses of the Uncom- pahgre. From Ouray we rode across the ranges to Telluride, Silverton, Lake City, Gunnison, and thence to Crested Butte and back, following a course which, ' The party consisted of H. N. Tod, Lionel Lindsay, C. H. Wittenoom, and the writer. W^MM& m i ft ACROSS THE SAN JUAN MOUNTAINS I,* 'i ^ t 'VUlV h rii; on the map, looks like a ug ire 8, with Ouray at the base of the lower loop md Crested Butte at the top. See map. The distance was slightly over 400 miles; the country traversed is beautiful to the traveler and interesting to the mining engineer, so that the experi- ence was sufficiently rich in incidents and information to warr t the account which it is my purpose to preser ^ left Ouray early on the 5th of September, 1902, with the intention of visiting two mines in the vicinity — the American Nettie and the Bachelor. A mile below the town the trail ascends the precipitous sides of Gold hill, and as our sure-footed mountain horses followed the zig-zag through the pines we found that each turn of the trail brought a steadily expanding vista until, halting on a projecting rock, we could see far out toward the north to the table- lands behind Montrose, across the near valley to the terraced dip-slopes of Triassic sandstone, down upon Ouray itself, cradled amid red rocks and golden aspens, and up beyond the town to the sentir«. best ore seems to iiug the contact with the overlying shale, in the manner illustrated in Fig. 1, where A and B are 'pockets' of ore reaching downward from the shale-sandstone parting and connected by a seam X T, which follows the line of division between the two rock formations. The pockets are full of crumbly oxidized ore intermixed with a little gypsum, while X T also carries some gypsum and a thin layer of black crumbly lime-shale, which suggests that it originated from the dissolution of an impure gypsum. The bedding is flat, with a slight dip to the northeast. <."^'-^m^mw^m\ .JS^. r'lif^.. i %,S^^ "'• ^iwm^ ^1 I i:' , n .1 1, ^: !« ^\\\ h , ' I i .1. f i:l| i'! 1 I{ AMERI' \N NETTIE MIME 5 ;.n(l the formation is crossed by almost vertical dikes which have evidently been the immediate cause of siicii fracturing of the sandstone as was favorable to sul)sc(|Uont ore deposition. In prospecting, it is found best to follow stringers o»" yrite or even mere 'walls' (slight fractures devoid ' .)re) that are parallel to tlu' course of the dikes. These dikes are peculiar; ihey are not mad** r" ." volcanic rock ; on the contrary, they consist of cb matf-rial, that is, fragments of sedimentary rock; in the /^ nerican Nettie mine the fragments were recog- nizable as pieces of sandstone, probably derived from beds not far away. The dikes thr" we saw were 2 to 4 feet wide, and were well defined by their distinct walls; the country near them was fractured and sheeted, a condition probably due to the disturbance brought about by the intrusions of volcanic rock, which are known to occur in certain parts of Cold liill. Not that the clastic dikes are of direct volcanic origin — quite the oontrary; the -re built up entirely of sedim.^ntnry rock material, v, h has been packed together and cemented 1 v the ..ater that has found its way into them; the^ .ccupy fractures that may have been, anr' nrobabl\ ,^ .-re, the indirect result of an intrusion, t • ' vsgh the neighboring formation, of true eruptive matter, such as has been referred to as actually occurring near-by. On the high ridge above tlie American Nettie mine there is a coarsely porphy- 'From the Greek, kla^tns, tiroken. It is employed to describe rocks made up of fragments, as distinguished from the crystalline. £1 f ^1 \ Jv- -^*p«^^-wm^ . . , w:mv':fw^w^^m^ ACROSS THE SAN JUAN MOUNTAINS ! ^ I ' 'M < f ritic diorite, which suggests an agency capable of having brought about the fracturing that led, first, to the formation of the clastic dikes and, subse- quently, to the circulation of the ore-depositing waters. The American Nettie has a new tramway, whose catenary curve sweeps om the high cliffs of Gold hill, and, with undeviating line, bridges the abyss of the valley. It is a picturesque bit of engineering. A descent of 1,820 feet is made in 4,200 feet. The span that crosses the valley is 2,100 feet long, and in that distance the drop is 915 feet. The engineers of the Leschen Company built it and, owing to the abrupt contour of the ground, they had to make especial provision for safety. The descending side has a cable IJ/^-inch diameter, while the cable upon which the empties return is one inch in diameter. The traction rope is ^ inch. To the latter, button-shaped clips are permanently attached, with intervening spaces, the length of which is regu- lated by the number of buckets in use. The buckets are automatically detached and attached to the rope, at the loading and terminal stations; at both terminals the buckets receive a retarding and accelerating movement, as they arrive and depart, respectivcl}, in order to diminish the vibration attendant on the re- moval of the load from the line, and the return of it into service. X I f 1 n ■XI •il '■H K^^ HHi ^■yHi ^^B^^Hfir ^^IB^ UK 1 •I , 1 '\h\ n ^ m H) f I > i !-:l Is- V'i 1 ' ' llilli i Cl^apter 2 THE BACHELOR MINE— TRAIL HORSES AND MOUN- TAIN TR..NSPORT— MINERS' COFFEE— A STRANGE DIKE— THE THEORY OF ITS FORMATION— DESCRIP- TION OF THE LODE. FTER leaving the American Nettie mine we followed the trail that took us around the northern ramparts of Gold hill, down into the valley, whence a road led to the Bachelor mine in Red canon. Two members of the party, who were unused to the mountain horse, marveled at his sure-footedness as we scrambled down talus slopes and threaded our way among loose blocks of fallen rock. It is my experi- ence that a good 'trail horse' will go almost anywhere that a man can go without using his hands, while the patient burro (donkey) will walk safely over ledges which bring a tremor to the hearts of those who are not mountaineers. All the exploratory work of the Rocky Mountain regions was done by 'packing,' that is, by the transport of supplies and machinery or the backs of animals. Both mules and donkeys are used in this service. When the former are employed they arc strung out in a line and connected by rope. A man rides the leading mule and guides the whole II ,f ACROSS THE SAN JUAN MOUNTAINS ■\l M> ? 1 cavalcade. Another man usually walks or rides in the rear. When burros ( the word 'donkey' being rarely heard in the mining regions) are engaged in packing they are not tied together, but each goes loose, and the owner drives them like a flock of sheep, though differing from the latter in that they have learned, from the narrowness of the trails, to walk in single file when that is required for safety. A mule will carry 250 pounds up grade and 350 pounds down, while a burro can manage to carry an average of 200 pounds. The mule requires to be fed, but the burro can eke out a precarious existence on the scant grass of the mountain slopes, and for this reason he has been most serviceable to the pioneer and the pros- pector; if the camel be named 'the ship of the desert,' the patient long-eared friend of the miner mighL well be christened 'the porter of the hills.' When we reached the Bachelor mine the noon-day meal was ready, so we accepted the invitation of Mr. George Hurlbut, the principal owner of the property, to take luncheon before going underground. It v:M not be out of place to refer to the food that miners get in localities like these; it is surprisingly good, as a rule, even at mines which are a couple of miles above sea-level and a corresponding distance from the main distributing points for provisions. The companies usually charge one dollar per day for board and lodging, where standard wages are $3 per shift. The f^re which the miner gets three times a day is superior to that of the second-class hotel of i |i :^ MINER'S FARE the neighboring mining towns and far better than that which is the daily portion of workmen in other countries. There is always one weak spot — the coffee; partly because it is nt prepared immediately before being se/ved and partly because it is made from adulterated mixtures, and largely because the average mine cook does not know the tast< )f real coffee — at all events, it is a concoction out of Keeping with the excellence of the remainder of the miner's fare and much better adapted for staining floors or removing boiler-scale. The Bachelor lode is closely associated with a clastic dike of peculiar <.haracter; the same lode fol- lows the dike through the mine to the east, the Khed- ive, and to the west, the Wedge. Light-colored sandstone and shale, belonging to the upper sub- division of the Triassic, constitute the prevailing formation; their dip is slightly southeastward and they are crossed almost at right angles by a dike, which inclines a little to the north and follows a fauit- iissure of small displacement. In the Khedive the sedimentaries form a low monoelinal fold broken by the dike-fissure, with an amount of dislocation so slight as to be difficult of measurement. The zinc- lead-silver lode of the mine traverses both dike and country. When small it usually follows one or other of the walls of the dike, and when enlarged it spreads out into both dike and country. The lode haf northing of 45 feet in 480 feet, but this is due not niuch to the angle of the dip itself as it is the fi I '• u:m • i ! Hi I H 10 ACROSS THE SAN JUAN MOUNTAINS result of frequent oflFsets caused ')y slips along the bedding-planes of the country. These do not fault the ore, because they antedate it, but they cause the vein to diverge to one side in accordance with the course of the fracture along which the dike first, and the lode-forming solutions afterward, f^nnd a pas- sage. The ore frequently spreads out between the bedding-planes of the sandstone and shale; it is also found in seams following fractures in the outer country that appear to be sympathetic to the main fissure occupied by the dike and the lode proper. The dike is usually about two feet wide. The dike, as seen in the Bachelor workings, is called by the miners, of course, 'porphyry,' but it con- sists of fragments of quartz, from sub-angular pieces as large as a thumb-nail to grains of sand, and of flat pieces of black shale; the latter are prominent, and give the dike-rocl a distinctly mottled appearance, as the accompanying photographs' show. They vary in size from microscopic fragments to bits several inches long. Besides these the dike contains pieces of sandstone, often micaceous by reason of sericite. A characteristic of the dike-rock is the arrangement of the shale fragments with tlicir longer axes parallel to the walls of the dike; this is more marked in some parts of the mine than in others, and it is usually most pronounced close to the walls. (See Fig. 2 and 3.) The latter form a distinct parting from the •These photographs I owe to the courtesy of Mr. Ransome and the U. S. Geological Survey. 'm• V'r-T — ■ ■'—-— I ')*■ ' i i''W"l :\t 'Ml i' ' , ' '' 1% X'.:jr'}:l:,\i.l Fig. 2. II !' Ill; ( ^' \\..f. I \ >!• r' -15 , 1 »' " 5 i f^ M ' -.] f 'i' ^ i I ^ Il- ia ACROSS THE SAN JUAN MOUNTAINS outer country, and sometimes are also accompanied by a sclvape. This, like the one we saw at the American Nettie mine, is a clastic dike and the origin of it affords Riiod material for speculation. F. L. Ransome, of the United States Geological Survey, has contributed an interesting paper* on the origin of this very dike, and he explains it thus: "A fissure was formed, accompanied by some faulting, and was filled, chiefly from above, by frag- ments of the soft fissile black shale, which does not occur in the stratigraphically lower beds exposed in the immediate vicinity, and partly by material from the lower light-colored beds forming the present walls." That this pseudo-dike is built up of fragmentary sedimentary rock, that it occupies a fissure, and that it contains no lava or other volcanic matter as a cementing material — these facts seem to be assured. The nice point about the problem is the mode of formation. Was it from above or below? Mr. Ran- so- accepts the first alternative, and in support of this view he is enabled to instance the sandstone dikes that Whitman Cross found in the granite near Divide, in Colorado, that, elsewhere, Darwin, Ussing, Irving, and others have described, and as- cribed to a filling from above. Hugh Miller found a pseudo-dike in Cromarty (Scotland) in which a mass "A Peculiar Clastic Dike near Ouray, Colorado, and its Associated Deposit of Silver Ore,' by F, L. Ransome. Transactions American Insti- tute of Mining Engineers, Vol. XXX., ,p. 227-236. u: •A Z ■fi y. ■7. } A CROSS-SECTION »3 3 'J / . ' ^ ' I. M ° • 'I L\ ' • '""rX•V'•^'L:- -• I Fiir Tis , S«N()iT«NJ 4M> JH^ie ({{y] CL-tiTlC B(«t 14 ACROSS THE SAN JUAN MOUNTAINS of sandstone working in from above (probably) con- tained fossils. Diller wrote a memoir' on the sand- stone dikes of California and concluded that they were injected from below. In the Lipari islands there occur masses of vol- canic tuff, hard enough to be fractured, which exhibit cracks filled in with fallen dust and scoria." But this is an entirely different kind of occurrence, as also is that observed at Pontgibaud (France), where a silver- lead vein occurring in granulite is shattered, together with its encasing rock, and, for a length of 10 metres, at a depth of 50 metres, contains boulders of scoria- ceous lava evidently derived from the alluvium that once covered the outcrop of the vein.' It is obvious that occurrences of this kind, at surface or near it, are quite different in their origin from a clean-cut frac- ture many hundred feet underground, of great length and depth and persistent width. It is, however, worth while to emphasize the distinction. As between filling from above by gravitation and filling from below through pressure, I am de- cidedly inclined to choose the latter. In the first place, no mining engineer familiar with the shifting of wall- rock would grant the idea of the maintenance under- ground of an open fissure, both large and crooked, in rocks so soft as these shales and sandstones, for a 'Bulletin Geological Society of America, Vol. I., pp. 411-442. " My authority is my friend, Professor John W. Judd, author of 'Vol- canoes' and Dean of the Royal School of Mines, London. ' Engineering and Mining Journal, p. 151, August 18, 1894. 'The Lodes of Pontgibaud,' by T. A. Rickard. I Tl f : i .'If r A DISAPPEARING FAULT 0^ ^\ IS i^\|^fe^3 •-^^iirf^ t . 1 SANDSTONE ^--:_=:] SLACK S.HA1.E l^j£rJ LIMESTONS LIME SHALE Fig. 4. p I^BKi ^^BIHIB f^B^^H ' les. Experiments were bring made in the use ■ a 5-ft. Huntington mill for re-grinding the coarser sand. This is likely to prove suggestive. The tailing is delivered to the cyanide plant, and is pumped into vats having a capacity of 275 tons apiece, wliere it undergoes solution for nine days. Tests were being made by Mr. Godfrey Doveton, who had charge of the cyanidation, with a view to determining whether the Johnson tllter-press cannot be advan- tageou^.ly employed in the treatment of the slime that overflows from the vats, at present the press is only used in connection with the precipitate from the zinc- I ■ ■! i I ( THE CAMP BIRD MILL 23 boxes. In Western Australia the large filter-presses have a capacity up to six tons apiece, with a tendency to increase. They were found to expedite the treat- ment of slime and to economize water. All experi- ments made in this direction should be useful because they point to a great economy of time and labor. The Camp Bird ore is one of the most docile. The total extraction of gold is fully, sometimes more than, 90 per cent of the assay-returns from the crude ore. The latter carried about two ounces of gold per ton at the time of our visit; the concentrate represents about 10 per cent in weight and 20 per cent of the value of the original ore, it contains 9 to 127^ lead, 12 to 15% zinc, 14 to I67i> iron, and 20 to 22% silica (as quartz). It also carries from 2/j to 4 oz. gold and from 11 to 15 oz. silver per ton. This product is sacked and sent on mule-back to Ouray, the charge for transport being $2.50 per ton, for the six miles of down grade. Coal is brought up as return freight at a cost of $4 per ton. The con- centrate is then sent over the range by way of the Marshall Pass, to the Denver smelters, 388 miles dis- tant, at a cost for transport, of $7.50 per ton and a charge, for treatment, of $7 > $8 per ton. The bul- lion, resulting from amalgamation and cyanidation, is sent under escort every day to Ouray, whence it is forwarded through an express company to the mint at Denver.'" "Since the d.itc referred to. an excellent account of the Camp Bird •nill and mine has been prepared by Messrs. Purington. Doveton, and Woods. See Transactions American Inr'-tute of Mining Engineers, 1902. !'i lii;- rl' (■ i I., i • 24 ACROSS THE SAN JUAN MOUNTAINS After partaking of Mr. Cox's hospitality we mounted again and began tlie ascent to the Camp Bird mine in Iniogene basin. As we surmounted the first rise we found ourselves in a wide amphitheatre of serrated ridgos with a broad gap in the direction whence we had come. Looking backward down Canyon creek, one could not fail to observe the fact of a succession of geological formations, on account of the variations in the color of the rocks. The road from Ouray first cuts through a gray ridge of S'lurian limestone, then passes over reddish beds of Upper Carboniferous lime and shale, which, in turn, are un- conformably overlain by the nearly horizontal beds of a Tertiary conglomerate that has a wide extent throughout the adjoining mining district of Telluride. This conglomerate, known as the Telluride formation, has a particular interest because it lies at the base of a great series of fragmental volcanic rocks (chiefly andesite-brec^ia) Prifl lav flows that enclose the majority of the important mines of the region. This is called the San Juan formation. The road intersects the base of the series a short distance below the Camp Bird mill at about 0.100 feet above sea-level, as is shown by the accompanying i)hotograph. where J B marks the line of separation between the two formation- (the San Juan and the Telluride). Our trail continued to pass over successive layers of the breccia and its intercalated flows of lava until we reached the summit of the range, at 13,800 feet. When a mine is situated in this country of andesitic breccia l^il If if '• if I i [i i h I ' . n I ll?i I i.:'ii' f:".t I i H' 1 I iifi r 1 ' ' i' ik ■ ■ i f f i i ' ' i 1 1 il 1 • r ,i^ I iiK Kkafmk Mll.I.S. NK.\k Olkav ;■ i flHHFii J SKJHHi ' III ' ii: ? : 1 9^Hlli 1 i ~W'MiMS^\ ^- if^^^^HB i i I It I; I II' Hi TiiK CkK>r iiK riiK Rani.k ami hik L'l'PtK Wokkini.s of hie ViK(iiNius Mine *• I V. A GEOLOGICAL SECTION 25 the distance separating the deepest workings from the sedimentary rocks at the base of the San Juan ormation becomes a matter of practical importance, because experience warrants the expectation that an impoverishment will be encountered when the vein passes out of the volcanic series. The Camp Bird lower adit, for example, is about 2,100 feet above the SECTION ALONG UNCOMPAHGRC CREE.K Fig. S. Telluride formation, so that there is plenty of room for further downward development. A generalized section of the geology and topography is given in the accompanying sketch, which I have borrowed from Mr. H. A. Titcomb's article in the Columbia School of Mines Quarterly, of November, 1902. In this sketch the name 'San Miguel conglomerate' appears, 26 ACROSS THE SAN JUAN MOUNTAIN^ ■ .fl i 'M (Ml r- I ri for it was the term originally given b; nitman Cross to the 'Telluride formation.' The old name was surrendered because of prior use by Texas geologists. So the name of the town replaced that of the county. The Virginius, a neighboring mine, has an adit — the Revenue tunnel — which strikes the vein at a point 2,400 feet below the outcrop and 10,800 feet above sea-level. The conglomerate is supposed to be about 1.000 feet deeper. A shaft has proved the vein for 900 feet below the adit, so that the total explora- tion on the vein extends for a vertical height of 3,300 feet, which is *^]ie deepest development attained by any mine in Colorado. The Virginius vein is remark- able in other respects also. It has been worked for more than twenty years. For the first 400 feet in depth the vein was stoped continuously, although its width only ranged between a finger and a hand's breadth. The ore was chiefly gray copper (argenti- ferous fahlerz) and averaged 400 to 600 ounces of silver per ton. At about 1,200 feet from the surface, the shaft, which followed the vein, entered a poor zone that extended for 300 feet further. At the level of the Revenue adit" another poor zone, about 150 feet thick, was encountered. The new vertical shaft, sunk from the adit, has found good ore, 30 inches wide, at 550 feet. The Virginius, by the way, " It is a pity that the word 'tunnel' is so often misapplied. In the above case, and ordinarily in mining, the word 'adit' should be used. A tunnel is a gallery or working that reaches from daylight to daylight, like a railroad tunnel. A main cross-cut or level that connects a mine with daylight is an 'adit.' t r THE VIRGINIUS MINE V has a large electrical equipment, which operates both mine and mill. The motor cars used for underground traction are remarkable in taking the high pressure of 800 to 900 volts from a bare wire placed about the height of a man's head. The power is generated from a succession of Pelton wheels, which use the water of Canyon creek. They present an interesting feature in the fact that the nozzles are worn out in ten days by the action of sand at high velocity, which is the consequence of using a stream charged with tailing from a mill. 1. Rhyolite and Andcsite. 2. San Juan Breccia. 3. Tellur.de Confftomerite. 4. Shale and Sandstone. Map of Teixuride District, Colorado. After U. S. Geological Survey. i;l I'l'i Chapter 4 THE CAMP BIRD MINE— STORY OF ITS DISCOVERY BY THOMAS F. WALSH — ON THE TOP OF THE RANGE. PON arrival at the Camp Bird, the superintendent, Mr. WiUiam Beaton, piloted our party through a portion of the work- ings. Both F. L. Ransome and ^1 C. W. Purington have recently described this lode in detail." A production, up to date, of about $7,500,o-}0 places the Camp Bird among the great mines of Colorado. It is also interesting as having been until lately the property of the man who opened it up, namely, Thomas F. Walsh. The history of the discovery of this celebrated mine is curious. The only outcrop of the vein for several thousand feet is in a small gully right at the head of Imogene basin. A claim was located on this outcrop in 1877, but nothing further was done because no ore of any value was exposed at this point. William Weston and George Barber, who were the owners, made a proposal to H. W. Reed and Caleb Reed that if they would run a cross-cut into the mountain, so as to cut the vein at about a depth " liuUctin No. 182. United States Geological Survey, pp. 89-90 and 200-204, and Transactions American Institute of Mining Engineerf, May, 1902. HOW THE CAMP BIRD WAS FOUND 29 of 150 feet, they could have the option of locating a new claim on whichever side of the cross-cut they chose. The cross-cut was run, and in due course intersected the vein. The Reed brothers drove 50 feet to the west and took up a claim on that side. This was then patented under the name of the Una claim. On the eastern side the Gertrude claim was pegged out by Weston and Barber, who, later on, sold it to the Allied Mines Company. This was in 1878. Subsequently the company extended a drift for 40 feet into the Gertrude ground, but found no ore of any value; later still, another 10 feet was driven, so as to make the distance 50 feet, and thus qualify for patent. This was in 1884. The ore in the last 10 feet was not assayed because the work was only done to fulfill legal requirements and the first 40 feet of the drift had yielded no pay-ore. But as a matter of fact the drift had, in the last two or three feet, broken into rich ore; it remained there undetected until 1896, when Walsh broke some sam- ples and had them assayed, thereby taking the de- cisive step toward becoming a millionaire. Moral: Never fail to test the ore of a drift that is penetrating into new ground, and never assume that ore is poor because it looks like ore you know to be poor. The rest of the story is well known. Walsh was an experienced miner who had met with some success both at Leadville and Rico. In 1896 he was manager of the smelter erected at Silverton lor the treatment of the ores sent down from Red Mountain by the bDI ii^ 30 ACROSS TIH^, SAN JLAN MOUNTAINS Yankee Cirl and Tiuston mines. Walsli ha 1, in 1894, nrja^anized the company that pui up 'his plant. In the search for silicions ores he investi.u^ated the mines of the surroutuiing country, not only those in operation, hut also the ahandoned prospects. He acquired the Hidden Treasure mine, in Itnosene hasin; this was a low-fT^rade silver-lead property, which has never done much. In July, 1896, he went to see how work was goine^ on at the Hidden Treasure, and incident- ally he n *iced some pieces of pink spar amid the rock-frasi"cnts scattered at the foot of the cliffs that form t'b upper limits of Imo,c:ene hasin. This pink spar he took to be lluorite, and because it re- minded him of Cripple Creek, where also he had mined with some success, he made a mental note of the occurrence. In the following September he re- visited the locality and climbed up into the old Ger- trude adit, from which he inferred the pink spar to have come. It was rhodochrosite; but no matter. It led him to take samples at tlu breast of the east drift. They were sent at once to Ouray to be as- sayed. The returns gave several ounces of gold per ton. More samples were taken and sent to Leadville for assay. These results were confirmatory, so he went to work quietly and began the steady consolida- tion of the adjoining property. Mr. Walsh's success was the reward following many years of most ener- getic search, a search backed by unusual experience in mining and extending over a large area that contained a great number of deserted old workings »3aKf?*^S7.# ON THE SUMMIT 3' ■A : likely to prove remunerative under new economic conditions. The main level of the Camp Bird is now over a mile in length, so that when we emerged from under- ground it became necessary to make haste in order to cross the range before dark. Ouray is 7,806 feet above sea-level, the No. 2 level of the Camp Bird is at 11,510 feet, and the place where the trail crosses ihe divide is at an altitude of about 13,800 feet. The trail is a good one in summer, so that we did not re- quire to lead our horses save in the steepest portions of the rise and in the abrupt descent on the other side. When we attained the summit a halt was called while we surveyevl the splendid panorama of moun- tains that lay outspread on either hand. Looking back over the course we had traveled we could see the shadows hastening to cover the valley of Canyon creek and the sheltered corner among the hills where Ouray lay concealed; in the far northeast the dark mass of the Uncompahgre plateau loomed purple in the fading light. Looking the other way, the grim desolation of time-worn summits and crumbling crags reached down into the gloomy gorge of the San Miguel, which suddenly broadened into the sun- lit valley of Telluride, checkered with cultivation and bright with the gleam of blue water. Beyond were green foothills, out of which arose the sculptured mass of Mt. Wilson, silhouetted against the settmg sun, and further still, northwestward, rim upon rim of far-ofif hills fading into the bourne of distant Utah, :| ^.' , * r 1 (T^of Ur 5 MILLS AND TRAMWAYS OF TELLURIDE-OPERA- TIONS AT A HIGH ALTITUDE— SNOVVSLIDES AND THEIR TRAGEDIES. HE descent to Telluride was ^"?^ tedious, for it meant leading our horses most of the way; and some horses are particularly slow to be led, however willing to be ridden; besides, the drop from the top of the range to the valley i^ just five thousand feet in the course of five miles. All the way down we passed mines and mills; of the latter, the new Tom- boy mill in Savage basin loomed conspicuous through the dusk. At first sight it seems curious to build a large mill at an altitude of nearly 12,000 feet, instead of choos- ing a site in the valley and transporting the product of the mine over an aerial tramway. This is a much- mooted question. As a rule the valley site is prefer- able, by reason of the availability of a water supply, the greater cheapness of fuel for power and heating purposes, the nearness to a base of supplies, the facil- ity that the tramway itself gives for transmitting materials up to the mine, the more kindly conditions of living for workmen, etc. If water can be secured 'i? 'V, ->- TRAMWAYS AT HIGH ALTITUDES 33 the erection of a mill close to the inine itself will save tlie cost of a tramway, that is, an amount ranging, say, from $20,000 to $50,000; but the water-supply of the high ahitudes is so closely dependent upon melting snows as to be uncertain, unless a reservoir or natural lake aflfords a chance for storage. Of course, if the mill i- at t!u mine, the concentrate has to meet the cost of carriage to the valley and this can be, in part, set ofT as against the expense of tramming the ore itself to the mill, if situated at a lower level. The Tomboy pays ^2.75 per ton for packing concentrate .roin the mill to the '-- -ul of the valley, at Pandora, and as the ore yields c ,. 3 to 12 per cent of concen- trate this cost represents . bout 25 cents per ton of crude ore. The item of fuel for motive power is elim- inated by the electrical transmission of power. Black- smith coal is carried by the pack-train to the Tomboy at a cost of $8 per ton, an amount one-half of which represents the expense of transport. The mill and othtr buildings arc heated by steam; in some cases by low-pressure boilers, in others by high-pressure boilers with reducing valves. In summer 40 tons of coal are consumed per month; in winter, 200 tons are consumed per month. Coal costs an average of $10 per ton, delivered at the mine. Water for milling piirpo'^cs is obtained from Lake Ptarmigan by a pipe- line one and three-quarter miles long." The lake is tiv- 'll™-.''"f "^"^u *"'' ". ^"'"- P'P"^' ""^'""^ " '■•educed to 4 inches at ( .i.nm.t; from the summit to the mill it is reduced, gradually, to 2'A u -i^rr , 'fM„"T ='"i°"'^.'' J^'^ I am indebted to Mr. John Herron. the manager ot the Tomboy mme. li !f if 1/ 41 '.'I,' 34 ACROSS THE SAN JUAN MOUNTAINS ■ , •); 1 just over the range and only 350 feet below the crest, so that light pumps serve the purpose. These are operated by electricity, which is bought from a large power company in the valley, at the rate of $80 per horse-power per annum. The Smuggler Union mine, which has its own generating plant, pays only $35 to $40 per h. p. per annum, but as against this, of course, are offset the interest and redemption of the capital used for an expensive installation. On the whole, therefore, it may be said that the comparison of conditions affecting the operation of a mill in the valley and that of a mill at the mine is without decisive result and depends entirely upon local factors. One of these is the ability to secure a good mill-site at a reasonable price. Another pos- sible factor is the snowslide. To a stranger the inter- ruption and damage from this source would seem to present a very serious obstacle to the use of a tram- way. It does, but to the same extent it affects all the operations in a precipitous snowy mountain region. Last spring'* the Smuggler-Union tramway was stopped for several weeks in consequence of the dam- age done by a slide, and during the same season the Liberty Bell mine-buildings were swept away, so that the mill was idle for four months. In the latter case 18 lives were lost, and the majority of these belonged to rescue parties that set out to the aid of those who were caught by the first slide. Successive rushes of snow entombed the rescuers. "That is, in 1902. I SNOWSLIDES AND THEIR EFFECTS 35 The snowslides that bring devastation to the mines of southwestern Colorado represent a recur- rent peril, for they are at work each spring with variable intensity. Of all evidences of Nature's power there is none so feared by the miner as this, 'the thunderbolt of snow.' After the winter snows have fallen and by successive thaws and frosts have become packed, there comes, during the period mark- ing the end of winter, a heavy snowfall, which, set- tling and accumulating upon the hardened surface of the earlier precipitation, is ready to be launched down the steep slopes of the mountains with all the suddenness of a thunderbolt and all the confusing ter- rors of a whirlwind. A slight movement may disturb the uneasy equilibrium; even a mountaineer's foot- fall may cause a huge mass of snow to become de- tached. In southwestern Colorado, where the moun- tain slopes are steep and but poorly protected by forests, there are more people killed each year from snowslides than in Switzerland, although the man of leisure who risks his life climbing the Swiss heights usually receives more mention in the daily press than the miners and other humble individuals that lose their lives in the San Juan while going to and from their labor. The destructiveness of a snowslide must be seen to be appreciated; buildings and tramways are as toys before its fierce oncoming and men in the path of its descent are as straws in a whirlwind. In fact, much of the damage is due to the vacuum caused 'by ■ V 1^3 |K:| U.I ^ III l! ^ ii! M ' ■ .. '■>. I 36 ACROSS THE SAN JUAN MOUNTAINS the rapid motion of a mass of snow and the cyclonic disturbance that follows in its wake. I have often watched a snowslide descending a neighboring ravine, when myself out of all danger. The thunder of its tempestuous descent first attracts attention, and then one sees the mass of snow gathering underlying rocks, uprooting trees, amid a quickly gathering mist of snow particles drawn fiercely by the whirlwind in the rear. The rushing mass will not stop at the bot- tom of the slope, but its momentum will carry it some distance up the opposite declivity, while all the forest trembles and the air is darkened with a snow mist. Ouray, Silverton, Telluride, and Creede— all in the region formerly known as 'the silvery San Juan,' but now identified chiefly with profitable gold mining- are localities where snowslides are of yearly occur- rence. One of the worst seasons in this regard was the spring of 1884, when a series of slides came down into the canon of the Animas, below Silverton, so as to blockade the Rio Grande railroad to Durango. In 90 days only two provision trains managed to get through; for this was in the days before the rotary plough. Nowadays such prolonged interruption to traffic is unknown. In March, 1902, a- -ady related, 18 men were killed at the Libert> ^ne, above Telluride; the mill buildings were s ^way and the tramway was severely injured. I i-- then the management of the Liberty Bell has built a V- shaped crib-work of solid timbers, filled with rock, in the path of the slide that did this damage. Their ,'.! s !/■. ■T. AM v& ' ^ u r ^ra |K 3a ^'- - "^Al - -^ 1 ill iMWli* 1 «*^- f - 1 m t f- « SNOWSLIDES 37 foresight was rewarded during the spring of 1906, for the snow broke away as before, but the slide was divided by this obstacle and did comparatively little harm. The slide that smashed the Camp Bird mill is called the United States, because it annually de- scends in a ravine past an old mine of that name. Snowslides usually follow a line of destruction marked out by them in previous years; this path is indicated by the removal of trees, forming a lane through the forest; it is also marked by the accumu- lation of debris, and by piles of snow that survive successive summers. The United States slide comes down a steep slope, it crosses the road to the mine, and descends into the valley traversed by the tram- way, the towers of which are protected by a timber cribbing. The Camp Bird mill is a little over half a mile away and had never been visited by this slide. Above the mill are steep hillsides covered with pine, which were considered to indicate immunity from such danger. In 1906 the mass of snow and the ve- locity of it were such as to carry the slide down the valley and over the edge of the hollow in which the mill stands, so that the vast body of snow dashed down the precipice and broke the mill-building like an egg-shell. It was a similar supposed immunity from danger that caused the Liberty Bell catastrophe; for, of course, the buildings were erected at a spot confidently believed to be beyond the range of any slide. ;v'i 'JK : :ikr 1 ii W Hi ! i '' II r ''-4 1' , 1 r it 1 1 ■j- f i if k\k^ 1 •J C^pUr 6 DESTRUCTION OF THE CAMP BIRD MILL — THE ASSASSINATION OF ARTHUR COLLINS — LABOR RIOTS. ANYON CREEK is illustrated on the page opposite as it ap- pears in summer looking from the Camp Bird mill toward Ouray; the photograph was taken soon after our visit and before the events of March 17, 1906. On that date a snowslide, followed by a fire in the ruins, completely de- stroyed the big mill shown in the rigl.t foreground of the illustration just mentioned. The next three pictures exhibit a scene of desolate grandeur; they are reproduced from unusually fine photographs given to the author by Mr. B. Kehoe. In the first, the track of the snowslide is seen through the smoke and steam ascending from the burning ruins; the nearly horizontal layers of andesite breccia form tiers rend- ered distinct by benches of snow and the serried ranks of pine. In the distance a tall peak, rising from snow- fields, pierces a troubled sky. It is a scene of im- pressive desolation and amid such a theatre of nat- ural destructiveness the surviving mill-buildings look insignificant indeed. In the second there is a nearer ! » ^•^r»aife ^^r^'-^m^. ^ "^WBUMidkiTM 1 1 1 i V i-S^J c^ijL. '• * "•.^:, ' - 11 ^i^^^^^^^^^StJ^^36ir'''^' li < 1 i <1 ;l In::! > I.iMiKiM; iKiu N Canvon Ckkkk rill' C;iiiii) liinl Mil. Huildings in the l-'orcjinmiid ^^ „^^ . ---dk-.-^tiK'^ ^ " Vv. - ^ S^ ~^ sr i m{ Wi . 1 ^^ 1 1 . • ! !^ i' 'l 40 ACROSS THE SAN JUAN MOUNTAINS second was dug out from under three feet of snow and timbers, also only slightly bruised; the third vas killed. The avalanche made no noise save when the timbers of the mill cracked, but the air was quickly laden with a mist of snow. The particular slide that did the damage was known, that is, its path in previ- ous springs was marked by a lane in the forest above the mill, but it had never been known to run so far or to be so violent; otherwise, of course, a different mill-site would have been selected. All of this happened on a Saturday evening; on Tuesday morning a fire was detected in the upper part of the boiler-house and this spread fast, so that all that was left of the mill was soon consumed. As the storage-tanks had been destroyed, there was no chance to fight the fire. According to Mr. Stephen L. Goodale, the odor of quicksilver was apparent for several days after the event. "The amtrikcr was shot. It is In- tombst' e that so en sificuously adorns the To luridc cemetery: upon it tl.. re i- this inscription "Erected by the 16-to-l \imers Union in memory of (then follows th- man's name). Born in Koojok Worn Finland. Uied at Sm. cjgkr, Colo., July 3, 1 >01, aged 27 years." Then follow these noble lines oi Longfellow: "In the world'< br >m\ field of battle, In the Iiivoii,,. .f life. Be not like dumb driven cattle — Fie a hero in the strife." I Ke- dfor -.am*' f. This — this is tlie prostitution of poetr mcrsiber, too, that no one has tv been puni the murder of tlv ci»• 7 • ' • /./ ■t^^:' Fig. ". '( ^ I .1 M « (I I 48 ACROSS THE SAN JUAN MOUNTAINS seen. This leader is the first part of the vein to show oxidation. The footwall is 'frozen' with quartz stringers, which merge into the country. The gen- eral structure of the vein suggests multiple fracturing with but slight actual displacement, and a shattering of the rock without much actual crushing. Vugs, or cavities lined with crystals, are frequent ; they are due to crustification, or crystalline growth, around the sides of spaces separating pieces of broken rock. The accompanying drawing" were made under- ground during a visit in 1901 ; Fig. 6 represents the back of a slope at the ninth level. On the hanging there is a quartz seam, J J. This is usually the rich streak ; if any free gold is to be found in the lode, it will be found there. The quartz is white and rather massive, with crystalline vugs. The next band, B B, is a strip of hard country, included in the vein; the part £ to D is also breccia, with some quartz; the foot-wall country, D F, is full of quartz stringers that drop into the vein; the outer country contains vugs and some quartz. On the hanging there is a soft shaly band, about three feet wide, which is used by the miners as a 'shooting course,' that is, it is rec- ognized as an easy line of fracture and separation be- tween the ore and the rock. Fit:;. 7, obtained in a neighboring stope. suggests the arrangement of ore in relation to the bedding of the breccia. The hanging-wall leader is represented by the stringer B B. A l a casing of soft shaly country corresponding to •; " 'shooting course,' as THE SMUGGLER VEIN 49 described in connection with Fig. 6. D D are seams of white quartz carrying iron-stained vugs. E E is a quartzose band. The included country in the mid- dle of the vein, from B to E, is mottled by brecciation and does not contain as much quartz as is usual. The foot-wall is hard. The lode yields a wonderful array of fine crystals of quartz, siderite, calcite, argentite, rhodochrosite, gold, and silver. The transparency of most of these, especially the quartz and the siderite, suggests an ex- tremely slow process of crystallization. Siderite, the carbonate of iron, occurs in handsome yellow crystals encrusting both quartz and calcite. Calcite was the last mineral to be precipitated, and it is found lying upon the quartz that lines the geodes or vugs. Rhodonite, the silicate of manganese, occurs in irregular bands, usually on the foot-wall or else in the main body of the pay-ore. Rhodochrosite, the carbonate of manganese, is occasionally seen in rose-red crystals. Gold is found in crystalline ag- gregates forming specimens of great beauty. Wire gold also occurs. Both the wire and the crystalline gold have the composition of the true alloy, Au Ag." In the upper workings, the native gold is purer. While the lodes of the vicinity, as a rule, have the general structure of sheeted bands of country rather than that of large fault-fractures, it is noteworthy that several of the poorer veins follow pronounced lines "A 'act determined by the late Arthur L. Collins, who gave me many of the data coiitamed in this description of the Smuggler-Union lode. [1 r ;1I 50 ACROSS THE SAN JUAN MOUNTAINS I? of faulting. I measured the vertical dislocations tha' coincide with the Contention and the AUeghenj veins; in the first case the displacement is 58 feet am in the second it is 21 feet. The Pandora faults th* V ^ ^ ^ Cross-Section of The Contention Loue. Smuggler about 50 feet." The Virginius vein ii faulted twenty feet by a cross-vein.'* In these casei it is the poor vein that follows the fault. "John A. Porter. 'The Smuggler-Union Mines, Telluride, Colorado Transactions American Institute of Mining Engineers. Vol. XXVI. p. 452. "C. W. Purington. 'Preliminary Reoort on tb» Mining Industrie of the Telluride Quadrangle, Colorado,' li. S. Geological Survey, p. 837 1 (r()af>tftr S THE CONTENTION MINE -AN AERIAL VOY\GE- GOOD MINE MANAGEMENT. \k K spent a couple of days at Telluridc, visiting the mines in the vicinity. Two of our party went up to the Contention mine, and avoided a long ride over road and trail by getting into one of the buckets of the tram- way, which makes a bee-line up the mountain side. The aerial voyage was made ^)cedily and safely, if not very comfortably. In wmter the managers of many of the properties find it expedient tc make their trips to the mines over the tramway, and in spring, when the deadly snowslide may launch itself down the mountain at any time, it IS much safer to travel in the air, not because the tram i^ always immune from this peril, but because of the shorter time to which one is exposed to danger in making the journey in a bucket, as compared to floundering painfully on horseback or toiling patiently uphill on snowshoes. The Contention is an interesting lode because it IS productive of gohl ore in a Tertiary conglomerate, not m the form of a bed of conglomerate impreg- ' I'? ■i i U i I S» ACROSS THE SAN JUAN MOUNTAINS nated with gold," but a nearly vertical vein-fracture cutting through a nearly horizontal formation and passing above this conglomerate into the andesite- breccia series and btlow the conglomerate into sand- stones of the Jurassic. This is an example of the great diversity of geological environment that dis- tinguishes the Telluride district; within a small area productive gold and silver veins have been worked not only in the Tertiary volcanics and the Tertiary conglomerate underneath them, but also in Jurassic limestone (the Sawpit mines) and in Triassic sand- stone (the Allegheny). This, however, is a subject too wide for more than incidental reference. The photograph of the Smuggler-Union tram- way illustrates the usefulness of this form of trans- port for sending supplies of all sorts to the mines at high altitudes. Timbers, lumber, coal, food, and tools are put into the buckets and, when neces ry, a couple of buckets arc spaced so as to carry the U 'i timbers or pieces of lumber. But besides this con- structive engineering, the photograph referred "o also affords a natural geological section. On the iace ol the cliffs overlooking Pandora it is possible to trace several successive geological formations. Thus J A represents the base of the series of bedded tuffs and breccias called the San Juan formation; then (dowr to C C) comes the Telluride conglomerate, and under it are the two layers of white sandstone separated bj a dark band of limestone, constituting the La Plata " Such as the conglomerate beds of the Witwatersrand, for example. ^mmmmk fiTJ ,#^ <»^\« ? I nflll f ^^' 1 11 W/'m M 'Ij ' ' I i 3 > I f >• Mar^hm.i. Mamn TIk' Sluriil.iii. MiiiilMt.i. anil riiiim Mine- \t GOOD MANAGEMENT 53 formation; still lower, along B B, the red grits and sandstones of the Dolores formation can be followed along the face of the cliff. Between the Telluride conglomerate and the underlying succession of sedi- ments there is an unconformity, which can be seen by an observer standing on the trail that ascends the opposite slope. The big mines of the Telluride district afford examples of good management and the close econ- omy that goes with such management. During the past fiscal year the Tomboy treated 85,726 tons of ore the average yield ^l which was $9.98 and the aver- age cost per ton, $5.85. With the help of the new mill, the costs are expected to be brought down to $5.50. The Liberty Bell mine, for the year ending September 30, 1902, despite snowslides and other un- foreseen delays, handled 67,439 tons for a yield of $7.15 per ton, at a total working cost of $5.53 per ton- while the Smuggler-Union, on a larger tonnage, has brought the total expenses to just under $4 per ton. In 1902 the average mining costs were $2.90 and mill- ■nj? expenses $0.90 for 92,917 tons. Summer costs were better than those in winter; for instance in April, 1902, the mining cost was $2.81 and the milling $0.74. foi 12,979 tons. The figures for mining include expenses up to delivery of ore at the dump. In referring to good management, it will not be out of place to mention the action of the manager of the lomb^y mine, who, when the old mine had evi- dently become exhausted, was enterprising enough H h^ 54 ACROSS THE SAN JUAN MOUNTAINS to secure options on adjoining ground, at that time giving promise of a good thing. Mr. Herron bought the Argentine for his company and thereby put the Tomboy on its feet again. In his negotiations he was supported by his directors, and the result is the possession of a mine that has made the shares of the company more valuable than they were at the time of its organization. Mr. Herron acted for the direc- tors, the directors acted for the shareholders, and although the transaction was a large one the share- holders were debited only with a bonus of $10,000, which was given by the company to the mine man- ager in recognition of his services. It is an incident worthy of record and does honor to all concerned. If managers and directors of mining companies al- ways took such a proper view of their duties, the industry of mining would gain thereby. A Fallt-Vein I'alltku. ; V = -1 5 =i - W3 r- j - a »!|%i U W' ^ ■M-1 f' -f til ^ lit L 1 iH jm ■■ 1 ■1 1 ^^1 I: ft w ■'^ - a (ri>af Ur 9 ON THE WAY TO SILVERTON — THE BRIDAL VEIL FALLS — FINE GEOLOGICAL SECTION — QPHIR — THE RED MOUNTAINS. N the 8th of September we started for Silverton, We took he recurrent zig-zag of the iiridal V^eil trail, and in an hour reached the top of the waterfall, .v'hose filmy traceries had origi- nated the name. The beauty of the waiTfall is gone, a sacrifice to ulih.arian engineering, which has taken the water to supply power to the Smuggler-Union mill. The pipe-line climbs to the place where once the rivulet flung itself into space, and the penstock stands where it paused for breath before its leap into the sunlit ravine. As we halted at the head of the trail, the San Miguel valley lay outspread with panoramic spa- ciousness. Nearly ho-'i/ontal lines of differently colored rocks in ordered >uccession gave the suggestion of long-continued natural forces building up the super- structure out of which the sculpturing hand of Time had chiseled the great array of mountain peaks that rose against the cloudless skies. Emerson has said somewhere that we ought to re«^ct "the nalurlang- samkcU which hardens the rwfcy m a million years, and imnm' If . 56 ACROSS THE SAN JUAN MOUNTAINS < \' ■ works in durations in which Alps and Andes come and go as rainbows." It is restful to contemplate this patient operation of natural forces in contrast to the unresting eagerness of man- —a nervous energy nowhere more marked than among the mines and mills which lie under the shadows of these very moun- tains. Such contemplation should conduce to equa- nimity. I think it does. The records of the geologi- cal societies show that geologists, as a rule, live long. Above the valley rise the short slopes of red sandstones of the Trias, surmounted by the white line of the La Plata sandstone at the base of the Jurassic, and above this distinct stratum, marked by a medial layer of dark limestone, there succeed the variegated shales and sandstones of the McElmo formation at the top of the Jurassic ; these, being fairly soft, have a gentle slope, partly covered by vegetation, and are topped with the gray band of the Dakota sandstone, at the base of the Cretaceous. All these rocks dip down the valley westward, so that the horizontal bedding of the overlying Telluride conglomerate brings out the unconformity distinctly. This Terti- ary conglomerate has a dark red color, as seen from a distance, and it belts the base of the steep cliffs above the valley conspicuously. It is about 400 feet thick just below Pandora, and is covered by the vast succession of volcanic ejectamenta, which rise tier upon tier for a height of 3,500 feet, culminating in serrated peaks that soar far above the uppermost limits of vegetation. A GEOLOGICAL PANORAMA 57 In leaving this wonderful geological section it will not be unfitting to suggest that instructors of geology in our schools of mines will find nowhere on the globe a better locality wherein to bring home to the student the relation between geology and mining, nor will they find, with convenience, a district that illustrates so well the working and the results of nat- ural erosion, the operation of which Hutton and Lyell emphasized as fundamental among the processes of nature. When we resumed our ride, we found ourselves on a trail threading a pine forest. In sheltered spots the wild flowers of summer still lingered, and the trail crossed busy rivulets, whose voice was the only sound disturbing the quiet of regions strangely de- void of life. Emerging from the pines, we found our- selves on the treeless waste above 'timber line,' and followed an easy ascent along the bare rounded slopes at the head of an amphitheatre of ridges. It was a lifeless desolation, bleak and still, until sud- denly a series of salutes rang out, to be echoed grandly from peak to peak. These were the blasts from mine-workings which we had not seen; they marked the noon hour. It was time for 'croust' (lit- erally crust), as the Cornish miners call the meal that divides their working time: so we off-saddled beside the first stream and ate our luncheon, while the horses nibbled the scant dr>- grass. It seemed good to he there under that serenely blue sky and amid an air that made "the world seem young and life an •jJBS "*A 58 ACROSS THE SAN JUAN MOUNTAINS •li* li. epic." Those who do not know the exhilaration of these high altitudes have not realized what perfect vitality means. On resuming the ascent, we were soon amid loose slopes of debris, over which the horses went with no more difficulty than ourselves, although the increased rarity of the air told on them very obviously. The trail was lost, and on choosing the lowest ridge to the soutli, we found ourselves eventually where we did not expect to be, that is, overlooking the little mining town of Ophir, which I knew to be out of our course to Silverton. We looked from a razorback ridge far down a precipitously steep slope into a dis- tant little green valley ; a white road threaded the cen- tre of it, and a cluster of dwellings, like match-boxes, seen so far, marked the settlement of Ophir. This is not Solomon's treasure-house, but as the slanting sunlight touched the clusters of yellow aspen upon the lower slopes of the valley we found reason enough for the name. Retracing our steps into the basin from which the ridge arose, we crossed to the eastern side, and finding a trail, ascended d crumbling ridge, from which we could see the ,hole complex of ranges stretching from Red Mountain to Silverton, and far beyond. We vere 13,200 feet above sea-level. It did not take long to regain our wind, and shortly the four of us were , kicking a way down the farther side, winding in and out of ihose semi-circuhr basins which arc so characteristic of the high country just N'- y i II ^Hr^jfl^^H A^ Ai]B| t K ' H. k II i hi w\ 1 m ■-'i |! ' 3 » •' 1 i' ' ^ ^ IL n V ' w\ A GLIMPSE OF OPHIR 59 above the timber-line. It was wearisome pulling unwilling horses over talus slopes, so we soon halted for a breathing space and took in the view. An amphitheatre of rugged peaks formed our back- ground; tiers built up of successive extrusions of andesite looked out upon a vast lifeless desolation of gray summits and dun-colored ranges, from which rose three flaming peaks, red as torches to anarchy. These, the Red mountains, are a landmark through- out the region. Their color is due to the solfataric action of thermal waters upon the iron sulphides disseminated through andesitic rock." At the foot of these iron-stained ridges are situated the famous Guston and Yankee Girl mines, which were so pro- ductive about fifteen years ago. The origin of the lodes is connected with that of the peculiar red summits, in that both are traceable to the activity of acid waters, which have precipitated rich silver minerals on the one hand, and, on the other hand, have re- moved the more soluble portions of the andesite, depositing additional silica, so that the resulting quartzose country has withstood erosion sufficiently to survive in the form of red summits, which now serve as beacons to the prospector." We reached Silverton before dark. "'Notes on Some Colorado Ore- Deposits,' by S. F. Emmons. Pro- cceditiRs Colorado Scientific Society, Vol. II., pp. 93-99. "This matter has been much discussed. See Theodore B. Comstock, 'The Geology and Vein Structure of Southwestern Colorado.' Trans- actiims American Instittitc nf Mining Engineers, Vol. XV., pp. 252 264 Also S. F. Emmon.s, Vol. XVI,, p. 809, and T. B. Comstock, Vol. XVIi., pp. 261-264. i ■ ■ 'A, ■- MICROCOPY DESOIUTION TEST CHART ANSI and ISO TEST CHART No 2' 1.0 I.I ]- IIIIIM ,"■ 132 1^ 140 2.2 2.0 1.8 1.25 IIIIII.4 1.6 ^ APPLIED IIVI/IGE In m- Chapter tO SILVERTON AND ITS EARLY HISTORY — THE FIRST SMELTERS IN COLORADO — PIONEEF S OF INDUS- TRY—SOME WELL KNOWN NAMES — RAPIDITY OF DEVELOPMENT. M i :\\>- i ILVERTON exhibited a condi- tion of bustling activity; the country tributary to it, up and down the Animas and along its tributary streams, has recently undergone a good deal of that new development which is es- sential to the maintenance of production in a mining district. In fact, by reason of the energetic development, particularly of gold mines, which has been going on ever since the fall in the price of silver in lo93, the surrounding region is today one of the most prosperous mining tracts within the Rocky Mountain area. The mountains around Silverton were first in- vaded by the pioneers in 1871, when the Little Giant vein was discovered by Miles T. Johnson. In 1872 an arrastre was put up, not far from the present site of the large modern plant of the Silver Lake mine. At that time the nearest trading station was at Conejos, in the San Luis valley. Until 1873 the ^^- > ^ tfl ■^:;lt !iu mi i!i / I: ' .1 ■'!•' if \M 1 s y i > '!ll j |5 '•■ 1 (.» \ ^ ' ,. i L^^MLa T 1 ■ < \ 1 i ^H i r J v|ti i r ^' I i .4' m^: EARLY SMELTING ENTERPRISES 6i Indians had legal control over the region, but this was ended peaceably by the Brunot treaty. Early on the morning of September 9 our party of four rode down the wide main street on the way to the Golden Fleece mine, near Lake City, about 40 miles distant. Just outside the town the road passes the entrance to Cement creek. Here there is a new pyritic smelter, which is close to the site of the old Green smelter, erected by Judge Green, of Cedar Rapids, Iowa, in 1874. The machinery for that early metallurgical establishment came on mule-back from Colorado Springs, over 300 miles; Colorado Springs being at that time the terminus of the railway. The first furnace was made of sandstone without any lining, and Mr, John A. Porter has told me of the advantages and disadvantages of this method of con- struction. It had one advantage: when the silicious portion of the charge was insufficient for a good mixture, the side of the furnace contributed the silica that was wanting! In 1876 the first water- jacket used in Colorado was put into service at the Green smelter; it was a round jacket three feet in diameter and was made by Fraser & Chalmers, at Chicago. The year before, in 1875, Mr. Porter had put in a siphon-tap, suggested by his experience at Eureka, Nevada, from which place he had come to Silverton. This was the second siphon-tap employed in Colorado; the first was applied at the Swansea works, near Denver, by Ahrents. Nothing remains of the old Green smelter save a cabin with a brick If '1 my 'i il Wf ' m ■M' u ACROSS THE SAN JUAN MOUNTAINS chimney, which used to be the assay-office of the establishment. This plant was the parent of the San Juan smelting works at Durango, erected in 1880, and contributed a.i important share to the early development of the surrounding region. Local smelters such as these have helped the exploration of the mountains. In riding across country, as we were doing, one would occasionally see, in contf'.st to the bright coloring of the aspens, a black patch of ground, suggestive of the gloomy gulf down which Plu'o snatched the fair Persephone. These dark patches are old slag-dumps, which have crumbled to dust, and serve as reminders of the little smelters that preceded the large centralized estab- lishments erected in later years at Pueblo and Denver. The memory of these early efforts has crumbled away, like their slags, but they are interesting not only as small beginnings of a great industry but on account of their human associations. They served to train many of our best men. John A. Porter has been mentioned in connection with the Green smelter; at the Rico works, first built under the name of the Grand View smelter, in 1879, such men as F. M. Endlich, Hofman, and Arnold successively got ex- perience and, in much later years, W. C. Brace, E. J. Wilson, and L. D. Godshall. The early seventies in Colorado saw the beginning of many reputations that are now well established. Dr. Edward D. Peters is said to have been a great champion of the reverbera- tory in those days; he built a smelter at Dudley, at ^^^mmum. METALLURGICAL PIONEERS 63 the foot of Mt. Bross, in 1872. The ores were rich in silver and copper, but loaded with heavy spar, so that although he began with only a calcining and stone blast-furnace, 36 by 42 inches in section, with water-cooled tuyeres, he subsequently added a re- verberatory furnace, having a 9;^ by 15-foot hearth, which was fired with spruce wood. The ores were unfit for smelting by themselves, but the smelter was operated with moderate success for two years. At that time West was in difficulties with a matte blast- furnace at Black Hawk, and Collom was bucking against the impossible zinc-silver ores of Georgetown at a little smelter just below Empire, near the forks of Clear creek. Colonel William L. Chandler was at Saints John, in Summit county, just over the continental divide, where the ore from a mine at Keystone was made into a silicate of lead in the fusion-hearth of a roasting reverberatory furnace. This was called 'matte' and was treated in a low shaft-furnace; the height from the tuyeres to the charging door being five feet. This stuff was sent to Empire, where John Collom was running the small shaft-furnace already men- tioned. The treatment was a failure until H. A. Vezin took charge of the works and produced good silver-lead. This was early in 1872 and was the first lead produced on a commercial scale on the Atlantic slope of Colorado. In 1875 Anton Eilers took charge at Saints John, but left in a short time in order to join Billings at the Germania works at Sandy, near i it ! f !li • 'I %u 'A m I 64 ACROSS THE SAN JUAN MOUNT MNS Salt Lake City, He was succeed d at Saints John by Franz Fohr, who, in later years, was manager of the Harrison Reduction Works at Leadville. In 1874 Mather & Geist started their smelter at Pueblo with two furnaces. This was the begin- ning of the Pueblc melting & Refining Company. A certain Profes? .leney at Animas Forks and a Professor Durier ,. Animas City erected smelting furnaces in localities as ill situated for fuel as for ore— doomed, therefore, to point a moral and adorn a melancholy tale. Richard Pearce had his first experience in Colorado in 1873, at an unsuccessful smelter erected near Empire, on the site of Collom's old works. At the end of 1873 this ill-fated establishment closed and Mr. Pearce moved to Black Hawk, where Professor N. P. Hill, not long arrived from Brown University, was in trouble with the pyritic ores of Gilpin county. Pearce and Hill joined forces and, under the advice of the former, an addition was made to the plant, where- by it became possible to treat the matte, which up to that time had been shipped to Vivian & Sons, at Swansea, Wales. This change of method made the Black Hawk smelter a financial success, and led, finally, in 1878, to the erection of the large plant at Argo, near Denver, where, under the name of the Boston & Colorado Smelting Company, it has since become so well known. James B. Grant had been recently graduated from Freiberg when, in 1878, he built a small one-stack FIRST SMELTERS AT LEADVILLE 6S smelter at Leadville. Within a year this was in- creased to eight stacks; and in 1880 Edward Eddy and W. H. James, who owned sampling works at Leadville, joined Mr. Grant in his smelting venture. That pioneer establishment is gone, but it was the parent of the Omaha & Grant Smelting & Refining Company. Anton Eilers has been referred to already. He was at the Germania plant from 1876 to 1879; in the spring of 1879 he started grading for the Arkansas Valley smelter, which was blown in on May 20 of that year. In these early efforts there is a personal equa- tion and a human interest lacking in the larger under- takings of later days, because they represented the skill, hopefulness, and energy of individual young men, many of whom have proved to be masters of the metallurgical art. While it must be amusing to those who are accustomed to the more patient prog- ress of older countries to read of a period within the memory of active men as being 'historical,' yet, as time is measured in a rapidly progressive mining region like Colorado, it does indeed seem long ago. "In a remote period of Western history, that is to say, 30 years ago," is a sentence not without a touch of humorous exaggeration to a European, but the rapid achievement of a new country outsteps the slow beat of the pendulum. a V i chapter U THE NORTH STAR AND SILVER LAKE TRAMWAYS- SOME CLEVER ENGINEERING — COMPARISONS ■ DOUBLE AND SINGLE ROPEWAYS — EUREKA ■ VETERAN MINERS. i •. •< mi S we rode along the right bank of the Animas, we passed the North Star mill, where John J. Crooke employed the old Au- gustin process, roasting silver ore with salt and leaching the resulting chloride with hot water, finally p "cipitating the silver on copper in the approved way. Farther up we came upon the Stoiber residence, 'Waldheim,' a 30-room house, with all modern ap- pointments, built by the former owners of the Silver Lake mine. Just beyond, in Arastra basin, we could see the Silver Lake mill and the tramway, which extends in swinging lines to the mine beside the lake at 12,250 feet above sea-level. One of the spans of this Bleichert tram clears a distance of 2,200 feet. In a total length of 8,400 feet, the upper division of the tram descends 2,100 feet, and has only 19 supporting towers. The lower portion — from the old mill to the new mill — is 6,200 feet long, wi h a m- V A i I i AERIAL ROPEWAYS 67 fall of 659 feet. The tram from the Iowa mine climbs the neighboring bluffs, and a little further up the Animas the North Star tram reaches the river from near the top of Sultan Mtn., a height of nearly 13,000 feet, making a descent of over 3,200 feet. Silverton itself is situated at 9,300 feet above sea-level. The North Star tram is two miles long, and con- nects the mill on the right bank of the Animas with a loading station at the entrance of an adit at 12,900 feet above sea-level. A two-bucket tramway, having a single span of 1,950 feet, carries the ore to two large storage bins situated in a gulch 604 feet lower down. Each of the two buckets carries 1,300 pounds of ore, the empty one being pulled up by the descend- ing loaded bucket. The cable descending is 1% inch in diameter, while the rope that carries the empties is 1 inch. The ore-bins, just described, serve as the terminal of a Dusedau aerial t.-amway, which goes to the mill, two miles down the mountain, making a vertical descent of 2,600 feet. At an altitude of 12,300 feet the tram crosses a mountain lake with a span 1,340 feet long, and lower down there are other spans of l.O.SO feet and 1,030 feet respectively. At the lower end, connecting with the mill, the final span is 900 feet long, with a fall of 380 feet, crossing the Animas river at a height of 150 feet above the water. The tension station is midway between the mill and the upper terminal. It is said that the gradient of the installaf )n is such that 30 horse-power is developed; but this power is not utilized. !| m 1 Mi < li '1 i i 1 \h \ ! 68 ACROSS THE SAN JUAN MOUNTAINS The buckets or cars are 40 in number, and each carries 600 pounds; they are placed at intervals of 600 feet, and travel at a speed of six feet per second. Fifty towers are stationed along the line, the highest being 71 feet. Two miles of steel ropes are used for this system, the total weight of them being over 30 tons. These numerous aerial ropes, spanning the inter- mountain spaces like great spiders' webs, are an important feature of mining in the San Juan region. We had already, on the previous days of our trip, seen the trams of the American Nettie, Bright Diamond, Grand View, Camp Bird, Smuggler Union, Columbia, and Liberty Bell mines, beside others, the names of which we did not know, so that with the group of three just referred to, near Silverton, we had, in the aggregate, observed a good many ex- amples of this kind of mountain engineering. Most of the recent installations belong to the Bleichert and Otto systems, in which the bucket is drawn over a thick stationary cable by means of a smaller traveling rope. The traction rope is usually from i/j to ^ inch in diameter, v/hile the fixed cable is from 1 to 13^ inches. The older Huson and Hallidie systems, with a single traveling rope, to which the small buckets are attached, are nearly obsolete except for short dis- t?nc''? and over easy contours. The need for fre- quent supports, the consequent less substantial con- struction, and their smaller capacity have rendered them less desirable as a means of transporting ere ■/* -«■ llHKAKrNi; 'Ik Ml. 'rilRori.ll THK Snow '.Man in thk 1! tki i ' .\n ICasikk MdiiK (IF Ik w ki. ! n Ill : ! i ■ 1 '^^ ■ i .' 1^" f irr- ^■^^N:, ' I 'I:'! ^ i I Bucket Attachnu'nt koi'K Ik \\i w.\\ s A Loading loriniiial Till- Webber Grip ri wff tl ill T *^Ti*-V.": ^^P^^^^^^^^^^WKt?* DETAILS OF CONSTRUCTION 69 over a rugged country. Experience now favors the double-ropeway system in spite of a cost of installa- tion that is 30 to 50 per cent greater than the single- rope type, because this difference of initial expense is soon wiped out by the cost of maintenance, which with the Hallidie type is nearly double that demanded by the Bleichert; moreover, in the matter • ' capacity, it may be said that the former is limited to, say, 75 tons per day of 10 hours, while the substantial con- struction and larger scale of the latter permit of a capacity that ordinarily reaches from 250 to 400 tons per day of 10 hours. On the other hand, it is claimed" that in a tram- way using the friction or compression grip, the rope will stretch after it is in use, and when this occurs the rope is reduced in diameter, so that the grip-jaws do not hold the bucket tightly, with the result that they slip and accidents ensue. This feature is avoided in the Leschen tramway, which uses from two to four bands that encircle the rope and take care of this dif- ference in diameter within reasonable limits, for, by tightening the bands they become as snug as the original arrangement. When a bucket is attached to the cable by a friction grip, it is done suddenly, and gives the rope and the entire equipment a jerk or jar. The operatic n consists in first moving the bucket to the desired attaching point, and the rope, running through the grip-jaws, wears them away, ""In correspondence received by the author from A. Leschen & Sons Kopc Company of St. Louis. ., >m 1 ■' \lf 70 ACROSS THE SAN JUAN MOUNTAINS I i-. '$ . b h>3 and then, when the grip is closed, it receives the sudden jar referred to. The particular objection to a tramway using a friction grip is that the traction rope is supported on rollers, the latter being placed below the bucket, so that when a bucket passes over a support, it clears it. The bucket, however, in passing raises the trac- tion rope about four feet. The cable then gradually lowers after the bucket leaves the tower. The result of this is not so apparent on a level tramway, but where there is grade, and especially where there is a cliff or a long span, the strain produced in the buckets in order to raise the traction rope tO the proper height is excessive, and will not only injure the traction rope, but it also affects the i xed cable immediately above. In the tramways employing a clip, such as the Leschen type, the traction rope is supported on sheave-wheels placed at the same relative distance as that of the bucket to the cable. In other words, the traction rope remains in the same vertical posi- tion at all times, and the clip or lug is so constructed that it passes over the sheave. Owing to the fact that in a tramway provided with the friction grip a bucket cannot operate around the terminal stations while being attached to the rope, it becomes necessary (upon detach the bucket at the terminal) to move the bucket around each terminal by hand. The labor required to do this depends upon the capacity of the tramway. In the Leschen tramway, the buckets remain attached COST OF TRAMWAYS 71 to the traction rope when traveling around the termi- nals. Only one man is required, and he is placed at the loading terminal to handle the brakes and to con- trol the flow of c.-e into the buckets. An argument in favor of the friction-grip tram is that, by having no lug on the rope, there is no bending of the cable at the lug, so that the rope will last longer. This is denied, however, it being claimed that there is less wear on the rope near the button than there is at any other place along the line; in fact, the clip is said to protect the cable. The eflfect that the clip has on the rope is said to be less than that produced by a friction grip. The various kinds of clip or button in use are so arranged that they can easily be moved from one position to the other on the cable in case this IS desired, and provision is made for turning the rope so as to distribute the wear evenly. The first cost of a tramway of this kind depends upon the contour of the country traversed, and the distance from the manufacturer who supplies the material. In the high altitudes of the San Juan, say, 10,000 feet or over, the cost of material for an in- stallation having a capacity of 200 tons per day of 10 hours would be about $2.10 per foot of tram-line, and the cost of freight, plus erection, would be about $1.15 more, so that the total cost would be about $3.25 per foot. A tramway, one mile long, having the capacity mentioned, would entail an expenditure of about $20,000. Actual expenditure for tramways in this district has ranged between $2.50 and $8 per m'^ i' m ' II B.i-.^j. | jy- ' i I :i ii 'H*' .£<(■ A ; «^'. 72 ACROSS THE SAN J JAN MOUNTAINS foot ; as a rule the cheap one proves the most expen- sive on account of the greater cost of maintenance and repairs. Tlie Camp Bird tramway is 8,550 feet long, with an angle station; the fall, in the length men- tioned, is 1,840 feet, and the cost, all told, was $55,094. It is a thorough piece of engineering work. At the present time it is worked on two 8-hour shifts, with a duty of 210 tons per diem. The operating cost is 17.6 cents and the maintenance 1^ cents per ton. A large amount of material is sent to the mine, as a back load, and the cost of handling this also is in- cluded in the figures just quoted. The spacing of the supporting towers is of course governed by the contour of the ground. In this re- ga- 1 the double-ropeway systems, with their inde- pendent fixed cable for bucket-track, permit of a comparatively more direct path and more uniform movement of buckets, because the cable can be stretched to a high tension, diminishing the deflection in the swing of the cable. In the case of the single ropeways, which both carry and propel the bucket, as a high tension leads to overstraining of the rope, it is avoided, so that there is greater dip in the cable and need for a larger number of supports. This is a decided drawback in a rugged mountain country. The automatic feature of tramways is apt to be exaggerated. For instance, it is the opinion of cer- tain capable managers that it is a mistake to depend too much upon gravitation, and that auxiliary steam- power will permit of the exercise of better control over \ AUTOMATIC FEATURES 73 the operation of the tram and the possibility, in con- sequence, of running it at greater speed. There is no doubt that an engine acts as a useful governor; on the other hand, the attempts to harness a rock-breaker to a tramway marked b> excessive gravitation have failed, because a rock-breaker in operation is esser tially a variable machine in its consumption of power. On the other hand an air-compressor has not this bad feature, and if a tram worked against an air-receiver it would have a self-adjusting governor of a useful kind. Most of the breakages, and much of the hard wear and tear, are due co variations in speed and bad control of tramways that have a difficult contour. In this connection it is well to point out that the modern tram owes much to the better modes of at- taching the bucket to the rope. The use of clips or lugs permanently fixed to the rope and employed as attachments for the bucket was found to develop un- even wear in the cable, and this method had the further drawback of hindering a change in the spacing of the buckets whenever wanted. The modern at- tachment grips the rope wherever desired, so that the bucket is hung at the will of ihe loader, and never exactly at the same spot. We continued on our way up the valley of the Animas and soon passed through Howardsville, which figures largely in the early reports made by R. W. Raymond, F. M. Endlich, and other Govern- ment officials during the 'seventies. It is now chiefly populated by Mr. Tom Trippe. In Cunningham gulch, Iti'" i 74 ACROSS THE SAN JUAN MOUNTAINS % if fi i s U :!'., Ih ' which IS close by, the andesite-breccia of the San Juan formation comes down to the Algonkian schists iseveral mines, such as the Highland Mary, Ureteba and Green Mountain, exhibit this contact between lertiary and pre-Cambrian terrains. The bes. ore Ob ained from the lodes, which penetrate both forma- tions is said to have come from the schist just below the breccia; this was especially the case with the Green Mountain vein, which had a large orebody im- mediately under the volcanics. The next tributary valley is Maggie gulch, where there are several younj mines, one of which, the Ridgeway, is of importance Ihe Ammas valley swings around to the north and the road brings the traveler into the main street of Eureka, the distributing point for the Sunnyside, Mastodon, Silver Wing, and other mines that have proved productive. Just .s Tom Trippe occupies Howardsville, so Rasmus Hansen represents Eureka These are among the very few of the pioneers who are still actively at work-strong brave men, who have crowded the romance and vicissitudes of mining mto their own lives; men with an indomitable pluck and a tireless activity, like that of the torrent of the Animas, which rushes by their cabin doors, sweeping past with a vagrant energy that heeds neither the gladness of the radiant valley nor the gloom of the savage gorge until, after many wanderings, it abates Its speed and hushes its voice in the still waters of the darkly flowing San Juan. Cl)af>ter 12 pr2^.>t.?^x,^°^^^-™^ TABASCO MILL-BUR- S?"colpER^ VEmr' '"'°^°^^^ ENRICHMENT EYOND Eureka we passed the ; Silver Wing and the Tom Moore mines, and just below Animas Fo/ks we turned eastward and started the ascent of Cinnamon pass. This is at an altitude of 12,600 feet, and separates the watershed of the Animas from that of the Lake Fork of the Gunnison river. On the divide is the Isolde mine, m the andesite-breccia, also the Bon Homme, in granite, and lower down we passed the tramway being- constructed for the Ta- basco mine. The bright glint of a thick copper wire bespoke a line of electrical transmission connecting the mine and mill with a power station situated on the farther edge of Burroughs Park. As the copper wire caught the sunlight I was reminded of the aid given by one metal to the other; the .ilectrical trans- mission of the energy of -^atei has done much for gold mining at high altitudes, where fuel for steam- power generation entails a cost that is almost pro- hibitive. Several successful installations have been ■ %>; ^■&if*' »'' ■• ' f 1 n J .i A Pack-Train on the Way to the Old Hl-ndreb Mine IN Cl-.vningham Gulch, near Silverton -;! « W7>W l; < # f ^i< I'' '= !i 1 i H t i '» J.] i ' :ii ■■« 1 tJifli .1 ill I'. I \r n : H U 5) i 5 ii Thk I-IKST Snow SiJ-VER Lakk Tkail ELECTRICAL TRANSMISSION OF POWER 77 mines above timber-line can be gauged by a look ai the trails, which frequently afford the only means of communication between the valleys and the mines. This is well illustrated in the accompanying photo- graph" of a trail to one of the Silver Lake group of mines. The Silver Lake installation was the first multi- phase plant in the San Juan region. It was erected eight years ago, and operates a great variety of ma- chmery, such as drills, pumps, hoists, blowers, machme-shop, etc. The line is three miles long. A compound condensing engine has replaced water- power because the generating station is on the rail- road, so that coal can be delivered cheaply (it comes from near Dnrango), while the water-pn-ver available was both insufficient and precarious on account of the damage to the long flume, brought about by rock- slides, snowslides, and the other difficulties of a high altitude subjected to violent extremes of heat and cold. Below the Tabasco mill we met a wagon heavily laden with bed-plates for an engine, beariug the name of the Colorado Iron Works; and soon after- ward, riding through a belt of pines, we found -our- selves in the open valley of Burroughs Park. This district has been, during the past two years, the scene of active prosp cting and some mining. We dis- "^"""^ ^^ and partook of hospitalities tendered by p. 4^'^'^"'"'"*'°'^ American Institute of Mining Engineers.. Vol. XXVI., I 4 IV li'J 78 ACROSS THE SAN JUAN MOUNTAINS 1 I ill ' Mr. George Peirce, who subsequently piloted us to the Cleveland group of veins. These are not as yet of economic importance, but they have characteristics that are interesting from a scientific point of view. They penetrate granite; the Monticello vein, which I saw, was about one foot thick; for the first 15 feet in depth the vein consisted of cellula*- quartz marked by copper stains, but otherwise it was said to be barren; lower down it became metal-bearing, and at about 45 feet deep I found a piece of copper pyrite coated with a gray film of chalcocite, suggestive of secondary enrichment and reminding me of certain experiments made by Mr. H. V. Wincheli at Butte, in the course of which the copper of a slightly acid solution of copper sulphate, containing also some free sulphurous anhydride (SOO, was found after a time to have precipitated a film of gray copper sul- phide upon the bright facets of crystals of copper pyrite." In the afternoon we left this locality and rode down Burroughs Park and nlong the Lake Fork of the Gunnison until, in the evening, we pulled up at the Golden Fleece mine, beside lake San Cristobal. The road at first goes over granite covered with an occasional patch of andesite-breccia, such as the one in which the Champion mine is situated. Then it cuts into the Algonkian schist and quartzite. Just ' i '' i ; I I: Km I i !>■ , Li c L ". i'^Pf ""len's have been described in detail lately 'The nTlr- 23 X\^°"^^'' ^^ "• ^' '^'"=''"="' l^^meering and Mining Jour- nal, May 23, 1903, *•. ',?* LAKE SAN CRISTOBAL y^ before reaching the lake the road and stream approach close to the contact between upturned schist and the overlying andesite-breccia. Near the lake, decom- posed andesite-breccia becomes the prevailing forma- tion. The road follows the contour line of the lake shore and afforded us a glorious canter in and out among scattered young pines; there came glimpses of placid water reflecting the resplendent coloring of the ""'5'?^ *1;^-^ ^'"st^ed upon the encircling hillslopes, and the bright warm tints of clouds that caught the sunset glow. Suddenly, in turning a corner, the road ran among a group of cabins and other buildings the busy aspect of which told us we were at our destina- tion, the Golden Fleece mine. U. S. G. S. :%*»■■■ V' ■^v'^^Uakf VMlVtJ-UC'-^^.Sfti <*t4M -•:-!»•;,■•#-- M if > ' '11: Chapter 13 THE GOLDEN FLEECE — A BONANZA AND ITS VICISSITUDES — GEOLOGICAL FEATURES — THEO- RIES OF LODE FORMATION — THE TREATMENT OF THE ORE. N the summer of 1896 the Golden Fleece mine shipped nine carloads of ore, weighing about ten tons each, the poorest of which netted $33,000 and the richest $49,500. In a few 'y^^^^fw months the bonanza yielded t^XS^^ $1,600,000. This rich ore was characterized by petzite (Au, 257c : Ag, 41%; Te, 34%) and ruby silver (proustite) scattered through a dark chalcedonic quartz or hornstone. The story of this mine exemplifies the uncer- tainties of digging for gold. In 1874 Capt. Enos T. Hotchkiss, connected with a government surveying party that was laying out a toll-road from Saguache to Lake City, caught sight of the outcrop, standing conspicuously above the hillside, and examined it. He located it as the 'Hotchkiss' mine, and had somi- assessment work done while he was engaged in his survey-work in the vicinity. As far as is known, he found no ore. A year later, when Hotchkiss had abandoned his claim, it was re-located by George iii ^ m ij I i:M FINDING ORE 8l vVilson and Chris Johnson, under the name of the 'Golden Fleece.' They began what is now known as the No. 1 tunnel, but finding only little stringers of rich ore they ceased work. Others did similar desul- tory prospecting. O. P. Posey found a rich patch of ore m the croppings above the No. 1 tunnel and took out several hundred pounds, which were packed to Del Norte and sent thence to the Pueblo smelter Then John J. Crooke took a lease and bond; he also extracted about $30,000 from the outcrop above No. 1 tunnel, which had been extended a little farther, without result. This was between 1876 and 1878.* In 1889 Charles Davis took a lease and bond; he did a good deal of work along the high croppings, and finally sank a shaft 30 feet deep, which struck a body of ore yielding $40,000 in a short time. Late in that year, 1889, George W. Peirce bought the mine for $50,000, and commenced vigorous exploration. He found out very soon, indeed, that Davis had extracted all the ore in sight, and the outlook was not cheerful. All the work up to this time had been to the north, on the supposition that the vein had been faulted in that direction. The new owners cross-cut south at the No. 2 tunnel, which had been previously extended a httle way, but had found nothing. The vein was picked up, but not much ore was encountered at first. They persisted, however, and within a year rich ore was cut on No. 2, and it was traced upward until it became easy to intercept the same body at No. 1. It was discovered that the former owners had been I'M ! I 1:/ li 1 +1 > H \ t I If* i iM I' .'^ I r . ACROSS THE SAN JUAN MOUNTAINS W'Wi' IS bl i < :ir i ^ i TlIK Tot.I. R()Ar> BKTWEEN OCRAV AND SlUE i m i'i n I! M ' i H ' r- 1 1 / f:/ i' ni ! h i:r I I i : 1^ ■ I 1 . i 1 ■ 'I ii i'ki J . 1 Thk V.M.l.KV ul I (IK I'm IIMI'AHI.KK Oiir.iN ill Miildl,. DiM.im-i-; ilu- MmmIiom' M,^;,^ R,>..iii1 THE GOLDEN FLEECE 83 withm ten feet of the main orebody of the mine, which from that t,me. and until 1897, was highly profitable. 1 he Golden Fleece vein strikes east and west, ap- proximately; ,t dips southward at the rate 01 33 feet m 380 feet. In depth it flattens, so that ti.e hade for the lower workings becomes 150 feet in 1,120 feet In the accompanying drawing, Fig. 8. the upper work- ings and the geological conditions are both repre- ul \I l"""'"! penetrates fine-grained breccia and tuffs, of the San Juan formation, until it runs abruptly into a coarse breccia, where it scatters and ends. The coarse breccia lies on the top of the finer series at an angle of 28°; the diflTerence in the rate of erosion renders the change of rock easy to recognize at surface, even if the abrupt cessation of the con- spicuous outcrop did not incite close observation The outcrop makes a comb, as much as fifty feet in height of hard smtery quartz, which, on examination, is readily seen to be a decomposed and silicified brec- cia, exhibiting various degrees of silicification from he vein itself, which is almost entirelv quartz, to the oyter country, in which the original' structure is but slightly obscured. In this outcrop there have been-and still are-found irregular patches of ex- tremely rjch ore. In the underground workings it can be seen that the vein itself follows a line of Iracture and brecciat.on; the twice brecciated country has been re-cemented with silicious waters, so as to form a vuggy or cellular veinstone. Pieces of country are to be seen enclosed within a coating of quartz The f $ t .f-i' rif. * IP ll.ii M 84 ACROSS THE SAN JUAN MOUNTAINS i .. 1^: /; sheeting of the rock explains the multiplicity of walls and ore-seams that confused those who have at vari- ous times exploited this vein. The outcrop ceases when the vein encounters the coarse breccia; so, also, in the underground workings the vein itself comes to an end with a suddenness that is, however, only comparative. The contact {-d B) has been considered a fault ; a good deal has been said concerning its regularity and clean-cut character. This, however, does not, I believe, accord with the facts. The so-called 'fault* is not a break or disloca- tion in the rocks ; it merely marks the division between the layers of fine-grained breccia and an overlying formation of coarse breccia; there is no smooth plane or wall or defined parting between these two forma- tions, but only a sudden transition which at a distance is more marked than near-by. The orebody of the mine was found in a tri- angular block of ground bounded on the one side by this 'contact,' A B, on the other by the hillside, B D, and along the base by the No. 3 tunnel, A D. The outcrop was patchy and irrporerished by leaching, the evidence of which is marked. This robbing of the croppings probably enriched the vein a little lower down. A branch vein, called the lima, which comes in from the northeast, appears to have played a part in determining the eastern or outer limits of the ore- body. Speculation concerning the causes that deter- mined this occurrence of rich ore is not hampered fi' ! THEORY OF ORE DEPOSITION 85 by too many facts. A correct explanation suffers from the lack of them. The contact existed before the vein was formed. The fracture, followed by the ore, passed easily through the finer-grained rock, but ceased abruptly when it met the beds of coarse brec- cia, because the force of fracturing was not only in- sufficient to overcome the resistance of the harder fragments contained in the latter, but it must have been dissipated by the encounter with a loose-tex- tured body of rock, much in the way that the power of a diamond-drill becomes wasted in passing into a shifting mass of loose conglomerate. As a con„.- quence, the energy of shattering was diverted along the contact, the vein-fracture ceased, and the later ore- depositing waters were barred from farther advance into the coarse breccia, save as a scattering confined to the neighborhood of the contact. At the third level, the orebody, which here is in the fine-grained country, was notably wider immediately at the 'con- tact,' and in examining the outcrop of the vein I noticed that it was difficult to decide upon the exact line of separation between the two formations, be- cause the mineralization extended from the fine into the coarse breccia so as to obscure the divisional p!ane. The deeper levels have found some small bodies of ore, and a good deal of money has been obtained from isolated pockets all the way down to the main tunnel or adit, about 700 feet below the third level. Several larger bodies of low-grade ore have also been lul !■ : 11 86 ACROSS THE SAN JUAN MOUNTAINS I I \ encountered in the deeper workings. Exploratory work is still going on, especially near the contact, where the chances for finding more ore seem to be reasonably good. Most o^ the rich ore of the Golden Fleece mine was shipped to the smelters, but the low-grade mill- stuff was treated on the spot. As the valuable metals were chiefly contained in telluride minerals (prin- cipally petzite, but also some hessite) the treatment — by concentration — presents features of interest. The mill was of latest design, erected by Stearns, Roger & Co. It consisted of rolls for crushing, Huntington mills for re-grinding, VVilfley tables for concentration, and a canvas plant for the treatment of slime. No use was made of amalgamation. The Huntingtons were provided with screens of 30 mesh, and experience showed late*- that 20 mesh would have been better. In treating 18,000 tons having an average assay-value of $10.25, half of which was in gold and half in silver, the extract! . averaged between 45 and 60%; 637o was the best result. The concentrate contained 55 to 65 oz. silver, 1 to 3 oz. gold and 12 to 187c lead, in the form of galena. The concentration was in the ratio of 12 to 1. It may be said that the experience with this ore indicated conclusively that a simple mill," with Wilfley tables and an extenc'ed canvas plant as the principal features, would have been adequate. "The mill was really designed for an ore containing galena and iron pyrite, both of which proved unimportant ingrp'lients when the mine became further developed. Cfyxfhv 14 SLUMGULLION GULCH — LANDSLIDES — THE CAN- NIBAL PLATEAU — A GRIM TALE — ROCK DISIN- TEGRATION—ACTION OF FROST. E remained for two whole days with Mr. Peirce, and early on the 12th of September our jour- ney was resumed. In crossing the valley of the Lake Fork of the Gunnison one cannot help noting the peculiarities of the surface. The eastern range, opposite the mine, is marked by a depression known as Slumgullion gulch. As seen from No. 3 tunnel it looks like a big landslide, the steep slopes of which have been obscured by weathering. However caused, it has reached down to the valley and dammed the stream so%s to form lake San Cristobal. It is said, by those living on the lake shore, to be still in mo- tion and to be extending farther across the valley. Slumgullion is commonly imputed to glacial ac- tion, but the observeo facts do not require us to go so far afield. Landslides, some of them of great ex- tent, dating back to early Pleistocene time, have been recognized and carefully studied in the Telluride and Rico regions. They are attributed to the penetration of water along bedding-planes and other lines of part- i k .1 1S I ,1. ^ V i :(l ! Ill in it '>.i' w !i M H H 88 ACROSS THE SAN JUAN MOUNTAINS ing. In the case of Slumg^Uion the porosity of the coarse layers of breccia permitted the entrance of water, which would reach down until a less porous stratum was encountered and then, if the dip-slope were toward the valley, the conditions would be ripe for a landslide. The geological conditions observed in the Golden Fleece mine would favor such move- ment if the bedding-planes dipped with the hillside; they dip right into the hill, however, and as a conse- quence the surface slopes steeply, at 30° and over. The same geological structure if carried across to the other side of the valley would explain the landslide of SlumguUion. In the earlier history of these moun- tains they were bolder than they are now, and when, at the* close of volcanic activity, earthquakes super- vened, then the landslides occurred on a colossal scale and were accompanied by a shattering of t'^e rocks, covering areas e iding over many square miles. The ascent ui SlumguUion was easier than it sounds, and as we filed along we were reminded by the mention of the Cannibal plateau, rising in bleak ruggedness to our left, of a tragedy the details of which no human witness has truthfully told. In 1873 a party of prospectors, intending to go to Fort Gar- land, in the San Luis valley, found their way up the river which we had left. It was a very severe winter, so that game was scarce ; they were verging on starva- tion, and on their last legs. Out of the five men, one, named Parker, survived ; he claimed that he went out into the woods hunting and on his return o..e of his '■S SLUMGULLION 89 comrades, rendered mad by hunger, attacked him with an axe, so that he had to shoot him in self- defense. Then the other three set on him, so that he had to kill them also. It is generally believed that Parker killed them to get the money they are under- stood to have carried. Game was not as scarce as he represented ; at all events he managed to support him- self until he worked his way out, and finally reached Durango, where he was subsequently arrested, con- victed, and sentenced to imprisonment for life. Two years ago he was liberated by the then Governor of the State. In his gruesome story he confessed to hav- ing been compelled by hunger to eat portions of his victims; hence the ominous name, which, like the gloomy brow of the Cannibal plateau itself, over- shadows the fair valley of San Cristobal. At the top of Slumgullion gulch the road turns eastward to Creede ; we turned northward and, pick- ing up a trail that plunged into a pine forest, we eventually found ourselves at the headwaters of the Cebolla and followed it down. We were soon on a well-beaten path— the old Ute trail, us 1 by the Indi- ans in their migrations across the Gunnison country. They are gone from these hills and are now huddled on the reservation; so also the game which they hunted ; that too has been driven away by the restless prospector. As we rode along in single file there was no sign of living thing for hours of travel ; we followed the Cebolla, fringed with willows and threading nar- row valleys overshadowed by cliflFs of architectural I ' f -.n m ii' Ml ' wh go ACROSS THE SAN JUAN MOUNTAINS n , '! ^'^,'i aspect, battlemented masses and moni'mcntal piUars, like Egyptian pilons, among which a babbhng trout- stream took its quiet way. The mountain flanks ap- peared to be buih of rhyoUte and rhyolite breccia. Occasional fragments of obsidian were found. Later we were in a granite country. While picking our way over the talus at the foot of high cliffs and noting the general air of destruction that had characterized much of the rock structure seen during this particular morning's ride, it was im- pressed upon the observer that frost action was the chief agent of disintegration. To mos; people who travel among mountains, and even to those who live at their feet, it is often a wonder how the rocks are broken, and when. Anyone who sleeps outdoors will note the fall of rock-fragments during the night, and to this fact. I think, is due the general immunity from such danger. The patient leverage (t ihe fi.*:,. is the chief agent in disintegrating the rocks, for, the max- imum density of water being at 4° C. or 39° F., one of the most powerful of nature's silent forces is set to work upon the water, which, having sought out the cracks and crannies of the rocks, is in the act of expanding. By day the temperature in the high mountain country is raised by reason of the penetra- tion of sunlight through the clear atmosphere, but at the approach of right there is a sudden cold, which is succeeded next day by another relaxation. Dur- ing these variations of temperature the moisture in the rock-cleavages undergoes an alternation of con- U': m CATHEDRAL 91 traction and expansion, which serves as an intensely powerful agent of disintegration. At noon we pulled up at a spot marked in large letters on the map as 'Cathedral' and found a solitary log cabin with a hospitable woman in command, who gave us dinner. Subsequently, when smoking a soothing pipe, we could appreciate the simple gran- deur of the granite forms, sculptured by Time and chiseled by the heat of day and the frost of night into buttresses and pinnacles simulating all the stern magnificence of a Gothic ruin— of a cathedral not made with hands, domed by the sky, and aisled with the green of the peaceful valley. _^ r-r— 'Sr- --!--' .- U. S. G. S. li ill it hi Y4 I If i ^ 4- 4 »i iJA 'IS t] I : I 1/ (I'll j,:|J ^' i 'H f . 11 i '{ M i ^\i';l ' '■!; L rJ ii \t) VI' I fl (ri)apUr 15 THE CEBOLLA HOT SPRINGS — THERMAL ACTIVITY IN THE ROCKY MOUNTAINS — ITS RELATION TO ORE DEPOSITS — THE GUNNISON PLATEAU. LL of the succeeding afternoon was spent in a comfortable ride down the expanding valley of the Cebolla, which now began to exhibit cultivation, until, with a long gallop through the cool air of the twilight, we reached the Hot Springs. Here we put up over night. From a distance the patches of white incrustation and clouds of steam told us of our approach to this scene of thermal activity. The links between vein-formation and hot springs which are to be seen throughout this region are not lacking in suggestion. The mining districts of the Rocky Mountains are rich in hot springs. In Colorado there are Hot Sulphur, Idaho Springs, Manitou, Canyon City, Glenwood, Poncha, Wagon Wheel Gap, Pagosa. Trimble Springs, Ouray, and others of less im- portance. Similar conditions obtain in the States of Idaho, Montana, and Utah. The occurrence of these thermal springs, rich in alkaline and other salts, in the midst of a productive mineral region, is not with- out significance. Apart from their scientific aspect, hJI THE GUNNISON PLATEAU 93 the hot i rings jilay ; useful part in the economy of man. "] le*. are the csort of people troubled with ailments tt quiring ri st and change of food; to the miners, who coait t them with rheumatism, indiges- tion, alcoholism, and similar troubles, they are ben- eficial, chiefly by reason of the opportunities for cleanliness, abstinence, and a simple diet — the last, to my mind, the especial boon of the thermal spring resort, because the miner lives in a world of sin and canned vegetables from which 'ranch food' and early hours of sleep will rescue him, bringing his inner man to a condition of normal healthiness. Next morning, September 13, we turned east- ward from the Cebolla valley and struck across coun- try for Vulcan. At the foot of a high ridge we passed the Old Lot mine, cheerfully active. The dump in- dicated a vein carrying two or three feet of dark quartz streaked with galena. Close to the latter oc- casional specks of native gold could be seen — a hand- some-looking ore. On the top of the ridge there was aflForded an extensive view of the Gunnison plateau, bounded to the north by the deep gorge through which the swift Gunnison rushes, and to the south by the bold outlines of the San Juan mountains. Look- ing eastward the outlying summits of the Cochetopa hills broke the sky-line, but westward the sage-clad ridges stretched in sober gray until they faded into the blue of farthest distance. Though tame as com- pared to the grandly picturesque mountain-land from which we had just emerged, this plateau yielded a ■i-: l ■ 'i UM m ■4 ^ 'M !; ^H 1 ' n 1 / L' 1 > • I i, til III!. I ■W .'II B 94 ACROSS THE SAN JUAN MOUNTAINS pleasure of its own in the glorious spaciousne^^s of a boundless horizon. This billowy succession of rounded hills is built up of Archean granite and Algonkian schist. We saw several outcrops of the latter, especially in the Vulcan district. Flows of Tertiary lava and layers of breccia form occasional flat-topped ridges with broken edges and tumbled slopes of debris. The occurrence of an area of schist is an interesting feature, for although there are oti.er stretches of these .ocks, represented by the actinolite schist of the Arkansas valley and the hornblende schist of the western slope of the Sangre de Cristo, this particular rock is unusual in the min- ing regions of Colorado, and is not regarded as a favorable terrain for precious-metal mining, a fact which is in striking contrast to California, South Dakota, and other productive regions. A Lode in Quartz-Schist. New Zealand. s o 'A in % I. ! ; n i : ^ l\Ji i ^» I, i In' '1 •! i' i( (.1 ( ' IUkrdii.hs 1'akk chapter 16 VULCAN — THE GOOD HOPE MINE -GEOLOGY OF THE VEIN -NATIVE SULPHUR AND TELLURIUM - ACID WATERS — THEORIES OF ORIGIN -RARE MINERALS. N arrival at Vulcan we pro- ceeded at once to the Good Hope mine, owned by Dr. Loui Weiss and others, who invited us most cordially to see the workings. This we did very gladly because the mine was well known as having been the source of the handsome specimens of native tellurium, which are to be found in many mineral collections; furthermore, I had heard of several peculiarities of lode-structure that aroused curiosity. The Good Hope vein penetrates a greenish-gray sericite or hydrous mica schist, which has the greasy feel and fine texture characteristic of that rock. It forms part of the Algonkian series of crystalline schists that overlie the Archean granite of the Gunni- son plateau. The vein has an approximately east and west strike; it dips northward, the hade being 40 feet in 500 feet. At surface the vein has an outcrop of heavy iron sinter, which eventually gives place under- ground to a band of country thickly impregnated ^l m ;ir5 a ill \i \ \ ' II . i : J M w fit ' Hmi li < \ i ii 96 ACROSS THE SAN JUAN MOUNTAINS with iron pyrite. The walls of the vein are smooth and soft, both features being due to a parallelism with the schistosity of the enclosing country. No selvage or casing was noticed, but the lode-matter breaks rather readily away from the country on account of a blocky jointing, which, added to the fissile character of the rock itself, makes mining operations danger- ous unless the timbering is well attended to. The rich ore is associated with streaks and lenses of iron- stained schist traversed by stringers of quartz. Native tellurium is frequently present, but the min- eral that carries the gold has not been detected with certainty. 1 found some spots of petzite, and it is likely that this is one of the enriching minerals. The accompanying sketch (Fig. 9) of the lode, as seen at the fifth level, will illustrate its structure. From J to B is the main pay-streak. On the hang- ing wall there are 3 to 5 inches of quartz, usually i.on-stained; then comes a bleached decomposed schist carrying a little quartz throughout. It is this white silky schist that usually carries th» telluride minerals. The band B is soft white schist, C is three feet wide and consists of massive granular-crystal- line iron pyrite in finely shaded bands that reproduce the lamination of the schist. D is another band of bleached schist. E is similar to C, but not so solid. The end liing country also carries a scattering of pyrite. In the upper levels there is evidence concerning the origin of he vein and its contents. The occur- i« IS 1 THE GOOD HOPE VEIN 97 rence of a body of native sulphur has been empha- sized, practically, by its combustion to an extent that endangered i. c mine. The adjoining ground in the Chimney and Vulcan claims was abandoned on ac- U! Il'.l '''•I'l' —LjjJJf ' Fic. 9. count of the burning of a similar body of sulphur. In the Good Hope there is a body of it 105 feet deep, 4 to 6 feet wide, and of a length which the o\.ners thought it unwise to determine by further driving. The top of the sulphur nearly coincided with the first level, 90 feet from the surface. This substance, which 1 '7i I ,, 1 : f ■'!• t 'J lii: M. if' h X 1^ 1 98 ACROSS THE SAN JUAN MOUNTAINS occurs as a grayish-yellow loosely coherent powod, was shipped in car-load lots to the Western Chemical Company, at Denver. It averaged 80 per cent sulphur and also 3 to 20 dwt. of gold per ton. The water of the mines on this vein is very acid and green in color. It carries over 1 % copper and 1.5 % sulphuric and sulphurous acids. On inquiry I was given the analysis of the water from the shaft on August 15, 1901 : Grains per gallon. Sodium chloride 1.82 Sodium sulphate 3-39 Calcium sulphate 4-35 Calcium carbonate 4-6i Magnesium carbonate 6.52 Silica 0.23 Organic and volatile matter 3.67 The water contained no free sulphuric acid, or at most a trace; there was only a trace of copper. It is the opinion of Dr. Weiss that the sulphuric acid and copper now found in the water of the mine come from the adjoining Vulcan ground and are traceable to the effects of the burning of the native sulphur, which lasted for two weeks in the Vulcan and Mammoth- Chimney workings. There was no acid nor copper in the water from the Good Hope shaft until after the fire, and it is probable that surface waters have since then perco'ated through the Vulcan workings and thence downward to the fifth level of the Good Hope, which is 100 feet deeper than the V^ulcan shaft. Apart from this fact, it is worth noting that the copper in ku I *.J EXAMPLES OF VEIN STRUCTURE '''''/.■■•rtn«--:'/-/?'-;--//'' Fic. 10. li, Fic. n. 00 .1 J J Ml J I .il 1 :i.3 ({ ii !, loo ACROSS THE SAN JUAN MOUNTAINS the Good Hope ore is increasing in amount with depth, specimens of the native metal having been found in the quartz from the lov^'cst level. At the first level there is evidence that the vein was shattered and that a certain part of it, at least, served as the vent for a thermal spring of compara- tively recent date. Fig. 10 and 11 were taken, the first within 100 feet of the shaft and the other farther eastward. They exhibit the shattering of a vein of opalescent quartz and the filling of the vein-fracture with geyserite, for a width of four or five feet. The substance that is here termed 'geyserite' has a specific gravity of 1.96 to 2. It is porous, with scat- tered bits of opal within a mass of grayish-white crumbly hard non-crystalline silica. On comparing it with a piece of geyserite from the Yellowstone, the identity was apparent. The banded opalescent quartz, so abundant in the upper part of the vein, has all the characteristics of such a substance when deposited from thermal waters, and it occurs in the Good Hope vein in various stages of hardness and texture. Fire- opal is to be seen in occasional brilliant specks, and many varieties of dark jasperoid quartz are found, beautifully banded. The gradation from geyserite to white sericite schist indicates that the latter contributed part of the material now occupying the vein-fracture, and the oc- currence amid the silicious sinter of occasional patches of a smooth unctuous white powder suggests THKRMAL WATERS lOI remnants of the mica that characterizes the enclosing country. These facts point irresistibly to the activity of thermal waters, that is, waters having a temperature higher than the mean annual temperature at the sur- face. Geyser action has, so Dr. Weiss tells me, been quoted in this connection by other visitors to the mine, but a geyser is a thermal spring that gushes" at the surface, and in this case we have no reason to suppose that such action occurred. Geysers are apt to be the last resort of a perplexea geologist. The supposition of thermal activity is based on the occur- rence, in the vein, of substances that are actually deposited from the hot springs in the Yellowstone and other places. In connection with this occurrence it is well to refer to the evidence of vein formation at hot springs, such as Walter H. Weed observed at Boulder, in Montana.'" At that hydropathic establishment there are two groups of hot springs, issuing from fractures in the granite and having a temperature ranging from 120° to 164°. These waters do not torm a surface deposit of sinter, but the fissures from which they issue are found to contain a mineral deposit. Many of the fissures have been sealed with this de- posit so as to form veins, the outcrops of which enable " ^^,^^" '* "''" '"'sndic word, meaning literally a 'gusher.' vv I. ^i"*^"' Vein Formation at Boulder Hot Springs. Montana,' by Walter Harvey Weed, United States Geological Survey, 1900 am Ml I i >•; il loa ACROSS THE SAN JUAN MOl'NTAINS one to trace their course ac.-ss the country. The vein-filling consists of a white or dark-gray material, which is mainly a mixture of chalcedony and stilbite, but also contains patches and bands of jasper, as well as included fragments of the granitic country. The illustrations given by Weed resemble the structure to be seen on the first level of the Ciood Hope mine. Opaline silica, in bands and curly layers, is seen throughout the mass. When freshly fractured it is usually dark-gray and very hard. The surrounding surface shows scattered fragments of jasper, chal- cedony, and other substances evidently derived from these deposits. On analysis they were found to con- tain an appreciable amount of gold, as much as 0.05 oz., and silver, as much as 0.4 oz., so that the connec- tion between ore formation and thermal activity is manifest. It is interesting to note that the author does not impute the source of the heat to 'unknown depths,' but to meteoric origin as "a part of the nor- mal underground circulating water of the region, heated by physical conditions giving it access to the still hot rocks underneath."" It would seem" that the Good Hooe vein existed as a pyritic band in tin- schist, formed by the action of feebly active underground waters such as, with ex- "Cr ri7,p. 250 " 1 iie reader i'= tminded that these data were gathered during a visit of a couple of hour^ while on a horseback reconnaissance across the coun- try, so that the writer's explanation of the origin of tlie vein is only a suggestion, prompted by the interesting featuies that have been briefly sketched. 'i^,:-.. '■■>'■ hi^- DioHiiK CuNTAtT (>N Silver Moixtain. neak Ophir N. 'ti' Cabin iu Kiijlit Ijimit G)riur '. n il 1 if t .m ii i.s I ; is I ! < Ull, ', :'; 1' ' t 1, ( '1 1 P.j !■ J' I > ,- tc j: GEOLOGIC ACTIVITY 103 trenie patience and slowness, are supposed to form similar lodes. Long duration of time for action and immense volume of solution compensate for feeble chemical activity and extreme dilution. The forma- tion of the fracture occupied by the vein and the cir- culation of underground waters, which supervened, may both have come in the wake of dying volcanic energies, such as were manifested in the adjoining region of the San Juan mountains. At a later date, after the Good Hope vein had been formed, it underwent a repetition of fracturing along which more intense thermal activity had play. A part of the vein served as a vent for a hot spring. This shattered the pre-existing vein and led to the de- composition of the pyrite, with the elimination of sul- phuric acid, the formation of an iron sinter, and the accumulation of a large mass of native sulphur. It is also probable that the liberation of iron salts, such as the proto-sulphate, afforded solvents for the gold, which was re-deposited in the lower parts of the vein so as to make valuable ore. The Good Hope vein is rich in uncommon miner- als. Tellurium occurs native, as a tin-white mineral with a metallic lustre. Occasional specimens exhibit rhombohedral prisms. It is associated with petzite, the telluride of gold and silver, and a new mineral, the telluride of copper." A greenish-brown mica- "'Rickardite, A New Mineral,' bv W. E. Ford. American Journal of Science, Vol. XV., January, 1903. this contains 40.51% copper, 59.49% tellurium. The composition corresponds to the formula Cu.Te.. \ 1 I •f ' ! 104 ACROSS THE SAN JUAN MOUNTAINS ceous substance suggests roscoelite, a vanadium mica, which occurs in association with telluride gold ores in Boulder county, and at Cripple Creek, Colorado, as well as at Kalgoorlie, Western Australia. One specimen, secured on the occasion of our visit to the mine, contained fine needles of berthierite, a sulph-antimonite of iron, which bears some resemblance to stibnite. The opal of the upper levels is said to have been rich, especially in the purple-tinted spots; this may have been due to a tel- luride salt. The distribution of the tellurides, to- gether with the native element itself, is another sug- gestion of the instability of these compounds in nature. As far as is known they are not characteristic of deep mining, but are more especially distinctive of that bonanza zone of gold lodes which is measurable from the surface and appears to be connected in origin with the conditions obtaining at the ground- water level. Of course, 'deep' is a relative term, and in this connection it refers rather to the vertical dis- tance from the lower limit of oxidation than to the position relative to the surface. LI ) I 1 vi^'^ ^ Cl)apUr \7 GUNNISON -THE DERELICT OF A BOOM- CRESTED BUTTE -THE IRWIN DISTRICT AND THE FOREST QUEEN MINE -SILVER VEIN IN SAND STONE -ANTHRACITE COAL. ROM Vulcan our trail took us over the eroded stumps of granite hills and across the river into the level s. etch of country over which the town of Gunni- son spreads itself drearily and wearily. Gunnison was a boom town, and when the wind goes out of a boom the wreckage is not enlivening Be- tween 1880 and 1885 there were three smelters at work. The combination, in the neighboring moun- tams, of iron, coal, and precious-metal deposits won for Gunnison the splendid title of 'a new Pittsburg.' The town attempts to covjr an area of two miles square, so that when you think you are in Gunnison you are out on the prairie, and when you imagine you are out in the country you are on a main street. In spite of it all, Gunnison wears an aspect of resigna- tion, as if to say 'it is better to have boomed and bust, than never to have boomed at all.' The next day, September 14, we started for Crested Butte, the centre of an important coal region. f i 1 ' M I i| vw i:. io6 ACROSS THE SAN JUAN MOUNTAINS The road follows the main branch of the Gunnison, a famous trout-stream known to every follower of Izaak Walton; the valley broadens at times into a goodly expanse of farm-land, dotted with cheerful homesteads. A few miles below Crested Butte the river is flanked by mountains, among which the rhy- olite cone of Round mountain and the basalt-capped mass of Mt. Wilkinson are conspicuous. Finally the traveler reaches the confiuenc" of several streams and a wide basin, on the western edge of which the town of Crested Butte has been built. A noble mountain, buttressed with steep cliffs and massive as an anchor- age for an aerial tramway to Mars, overlooks the town from the east, and has given it the name of Crested Butte. It is a big stock of porphyrite." On the west and south the gentler slopes of Mt. Wheat- stone, fringed with pines, merge with the valley, and to the north a perspective of successive peaks in- dicates the Ruby range. These gain height and mys- tery as seen through the smoke from the coke-ovens of Crested Butte, lying huddled under the long shad- ows of evening. In the centre of the town we found a barrack-looking building, which turned out to be a c'ean and comfortable hostelry. Next day, the 15th, saw us on the Coal Creek road, on our way to Irwin and Floresta. On both sides of the canon the hillslopes were a desolation of burnt timber, a glimpse of that destruction, through careless fires, which is "Crested Butte Folio. U. S. Geological Survey. 'Igneous Rocks,' by Whitman Cross. \ [ . A |i i t\ i Mt Tkk-au.i a HiGHLANn Mfadow I ^ 1 ii i-i ■rflMl Mi [Hh 1 ii ■ im.,'^ THE IRWIN DISTRICT 107 \ gradually causing the deforestation of Colorado. The actual burning of good trees is bad enough, but the effect of such fires on the young growth does the more serious injury to the possibilities of a future supply of timber from these devastated tracts of mountain-land. As the higher altitude was gained, the scenery improved and became bolder. We were passing through a porphyrite country, and the large frag- ments that had rolled to the roadside showed hand- some crystals of feldspar. A winding trail took us northward from the westbound road and brought us to the deserted hamlet of Irwin. The Irwin mining district was active in 1880 and succeeding years. The Forest Queen mine is credited with a production of ever a million dollars. In 1893 the fall in the price of silver flattened out the life of the camp, and until lately it has remained practically deserted. Quite recently a consolidation of a group of mines has been effected, and there is now promise of some activity. We visited the Ruby Chief mine, under the kind guid- ance of Mr. P. F. Ropell. The Ruby Chief vein traverses a bedded series of coarse sandstone and shale belonging to the Ruby formation of the Upper Cretaceous. The vein oc- cupies a fault-fracture, as was indicated by a break in the continuity of a layer of shale seen underground. The strike is northeast-southwest, while the dip, northwestward, departs only slightly from the ver- tical. The accompanying sketch. Fig. 12, gives a I [i 1 io8 ACROSS THE SAN JUAN MOUNTAINS 1:1 t I .■,, ij^i '^.h i i < r ■ ! . -, ■ f ■ • ! ' 1 f f i'ii . a \ M iv h typical section of the lode. In the foot-wall there is a band of shale. From -,^ to B is a laminated casing of sandstone seamed with veinlets of quartz, which exhibits comb structure. B C is a 6 to 8-inch vein of white quartz, streaked with arsenical pyrite, or mis- pickel. This is the best ore. It usually carries ruby silver (proustite) and brittle silver (stephanite). Selected ore contains 65 to 100 oz. silver, and from 10 dwt. to one ounce of gold, per ton. This vein or 'leader,' B C, is usually characterized by a defined streak of pyrite, accompanied by zinc-blende, which speckles the quartz in lines parallel to the walls of the vein. C to D is mottled, obscurely brecciated coun- try, with quartz surrounding the fragments of sand- stone, and impregnated with arsenical pyrite. D to £ is an outer band of obviously brecciated sandstone containing but little evidence of mineralization. The crystalline quartz, lining cavities or 'vugs,' is a marked feature of the lode, and especially of the inde- pendent quartz-veins that occur in the outer country alongside of the main vein. The quartz incrusting the brecciated sandstone within the lode, appears banded, due to the contrast between layers of quartz and mispickel. Rhodochrosite was seen in a few specimens. Mr. Ropell informed me that the best ore had been obtained from the vein at the horizon where it traversed the conglomerate beds, which form an integral portion of the Ruby formation. To these notes may be added the fact that porphyrite occurs in the vicinity. Mr. S. F. Emmons has noted that the THE RUBY CHIEF VEIN 109 J :v:-: 'tv../' » m ■"••■v#int%r-.2'/;i^ - r'-\' •:••. •.^!^\:i'::i'.>^UM^M■■••■••'• ;i;- Fig. 12. ii ■ i i I ! ' .'VJ ' i^L 1 1 1] ill 1'^^ no ACROSS THE SAN JUAN MOUNTAINS porphyrite occurs apparently as an intrusive sheet fol- lowing the bedding of these sedimentary rocks, al- though the compound fracturing associated with the vein-structure "often gives it the appearance of a dike within the mineralized zone."^' Leaving Irwin, we retraced our steps for a mile and crossed the shoulder of Ohio peak at Kebler pass, named after the president of the Colorado Fuel & Iron Company. The winding road was followed through a pine forest until, on the northwestern slope of the ridge, it descended abruptly into a narrow ravine. To ride over a deserted mountain road and then to come suddenly into full view of a compact little mining settlement is a sensation which does much to break the monotony of cross-country riding. This was Floresta, boasting the only anthracite mine west of Pennsylvania. The old anthracite min*^, known as Smith's, near Crested Butte, has Le>.n worked out, and the new anthracite region, tributary to Paonia, now being prospected between the Gun- nison river and the Anthracite range, is yet in an immature stage of develc^iment. A note on the Smith anthracite mine will be proper here. It was located 21 years ago, and opened in 1882 by George Holt, now of Chicago, Howard F. Smith, now of Elkhart, Indiana, and Dr. William A. Bell, of Colorado Springs. They erected a breaker, installed the requisite machinery and operated it for " Anthracite-Crested Butte Folio. United States Geological Survey. 'Description of the Elk Mountains,' by S. F. Emmons. ANTHRACITE MINES III several years, until it was acquired by the White Breast Fuel Company, in which Messrs. J. n. and J. T. Kebler were interested. Shortly afterward it was acquired by the Colorado Fuel & Iron Company, which has since held and .steadily worked the mine until April, 1903, when it was finally abandoned as worked out. The vein averaged from three to four feet in thickness, and the coal was of excellent quality. An approximate production of 5,000 tons per month was maintained. A spur of the Denver & Rio Grande Railroad from Crested Butte connected with the breaker. The incline from the mine to the breaker is 1,800 feet long, with a pitch of 45°; it is the longest and steepest in the State. The gravity system was employed. 1 \ \ \ Upturned Strata of the West Slope of the Elk Mol'nt ains. The light-sh?-' " stratum, Jura-Trias ; that to the right of it. Carbon- iferous ; to i..^ left, Cretaceous. From Hayden's Report of 1874. Craftei 1$ m ii T!l!', ( OAI MINE AT FI.ORESTA- )\V ANT!iR.\- Ciri. IS i<)RMED— METHODS OF MIMING— iFfE RPF.iKEF^^V PANORAMIC VIEW. ^"l^C^ "^'^SiK ^^^ '^"^^ ■'^*^^'" ^^ Floresta is '."^ t^ T^^i'-'nAmW' three teet thick, and (lii»s north 'It an angle of about 20°. It lies with the iiillslope, the ravine i having cut into tlie seam so as to give a line ot nitcrop on both sides. Tlie agency that was chiefly instrumental in the de- velopment of anthracite from bituminous oal is indicated by the porphyrite, Jiich appears in the form of dikes in thi railroad < iittin^ and is clearly to be seen capping the lillside. The coal now being exploited occurs at a geolog.-^' 1 horizon which is 1 15 feet above the bast- of the I-aransie formation, belong- ing to the Cretaceous. There is also another, poo ^r seam, one hundred feet higher. These coal leasures are covered by a sheet of porphyrite, whicl xtend for more than a mile aloiit^ the north slf : oi' Anthracite range, the name of the muc i senai 4 ridge behind the mine. The metamorpi effect o: the p' rphyrite on the coal is readily apparent; where the met imorphisni of the sedimentaries is li ist, non- coking uitumin jus coals ; e found; where i meta- \ i ill Mi ill E H-^fl i \- 1 I H n 1^: J w fl u I |i»;ffl i\<: 1 V THE FLORESTA MINE "3 morphism has been present, but not severe, the coking coals occur; and in regions of intense local meta- morphism the coal has been changed to anthracite. It has also been observed" that a dike cutting across a coal seam affects its chemical and physical com- position for a short distance only, but an intrusive sheet will affect it for a greater distance and over an area commensurate with the extent of the eruptive itself. The output of the mine at the time of our visit was 100 to 125 tons per day. The manager, Mr. Thomas McLaughlin, to whom we were indebted for man^ courtesies, informed me that there is much difficulty in keeping miners at Floresta, because the mine is not in operation, on account of snow, for more than half the year, which prevents men with families from going there. Moreover, the narrowness of the seam and the conditions of working are such that only the most experienced miners can earn a good living. The work is much more arduous than that of ordinary lode-mining, because of the cramped space and the subsequent disposal of the output. Owing to the slight dip of the seam, it is difficult to handle ^ht coal underground; the chutes that carry the product of the face to the entry are made of No. 16 steel sheets, 3 feet wide, laid on the foot-wall, and nailed onto sides made of 2 by 6-inch scantling. When in constant use the angle of inclination is sufficient "George H. Eldridge, Anthracite-Crested Butte Folio. United States Oeological Survey. J 114 ACROSS THE SAN JUAN MOUNTAINS II 1^ M : I ', \.\i ^1, li to keep the chute clear, but if the steel lining becomes at all rusty, th^ slope proves inadequate for the auto- matic descent of the coal, and the miner jumps into the chute and toboggans down the incline, pushing the coal before him with his feet. The men jet 90 cents for 2,600 pounds, of which it is estimated that 2,000 pounds is clean coal, the balance going over the culm heap. Wages, as I got them from a scrutiny of the pay-rolls, averaged $4.25 per day, with about 30 men at work. The men are largely Austrians; scarcely one-half of the miners speak English. In the mine we found that pillars to support the roof were left 15 feet wide, while the rooms or stopes were 25 feet across. The drilling is done with ma- chine-augers, the hole being begun with a 2^-inch bit, and finished with a l>4-inch. Holes are made from 4 to 6 feet deep. Coarse black powder is used; it costs the miners $3 per keg of 25 pounds. The product of the mine is sent to the breaker, which has a capacity of 600 tons per day. Five si •■? are made. The coal from the tipple goes over two sets of screen- bars, the fine passing direct to liie picking-tables and the lump to the breaking-rolls. These are toothed rolls of the usual type. Then follow revolving screen.'. The culm is hand-picked as it runs down the chutes. These chutes for slate-pitking are double. Each picker (boys and old or crippled miners) draws past him just as much coal as he can thoroughly clean, so that the coal is handl d once only. THE FLORESTA MINE "5 6 The upper landing is 10,175 feet above sea-level. This makes Floresta the highest coal mine in the United States, if not, indeed, the highest in operation ■ n\ ^ ♦**•/♦ •• ♦ ♦ * » -_-=^ ■ ■ ' A •*.* , X ♦ ♦ tJ-^— r^^" • . • • . : •■.•••••N.-V.- .V*"-^* •.•.•.■•■•. • ../♦ ♦ ♦ ♦ ♦ Fio. 13. anywhere. An average analysis of the anthracite shows: „ „ Per Cent. Fixed carbon 37.51 Volatile combustible 7.62 Moisture qj^ Ash .'."." 4;is The roof of the seam is a 30-foot bed of sand- stone; the floor is in shale. Along the railroad grade HI I r # ^(^ 1 f < > ■ J ■' -1 ii6 ACROSS THE SAN JUAN MOUNTAINS A MAGNIFICENT VIEW "7 9S o a . Ut/1 •< £■3 II < « Li ♦^ o there are afforded several good sections of the sedi- mentary rocks enclosing the coal, where they are intruded by porphyrite. A typical section (Fig. 13) exhibits a dike, evidently a porphyrite containing large distinct crystals of feldspar. The bed of shale traversed by the dike is hardened near the por- phyrite, and otherwise altered into a dark massive rock. Fragments of shale are included within the dike. The joints in the sedimentaries cross the dike clearly, and are, therefore, later than the intrusion of the latter. There is no distinct parting or wall be- tween the sedimentaries and the eruptive. On the railroad grade, and about a mile from Floresta Itself, a promontory of rock gives a mag- nificent view of the Anthracite and Ruby ranges. To the left are dark pine woods sloping from Ohio peak with an inclination that reproduces the dip of the porphyrite flow and the coal-beds underneath; in the middle distance, and contrasting with the dark array of pines, are brilliantly tinted foothills whose rounded contour indicates the softer sandstones of the Cre- taceous. Beyond these rises the abrupt mass of Mt. Beckwith, built of porphyrite. Above the northern horizon is Gothic Mountain; to the right, and com- ing down to meet the other half of the picture, is the red Ruby range with its serrated comb of dikes, which can be seen extending in jagged line down to the valley itself, through which a trout-stream winds in and out until it is hidden by the precipitous face of '..'.» ii8 ACROSS THE SAN JUAN MOUNTAINS Mt. Marcellina, a dome-shaped laccolith" of por- phyritic diorite. Far off, palpitating amid the haze of forest fires, are ranks of distant hills whose purple The Laccolith of Mt. Marceluna. After Whitman Cross. forms are faintly silhouetted against the flawless blue of a Colorado sky. " A 'laccolith' is a body of intrusive lava. It does not spread in dikes or sheets, but gathers into a mass or core, wrhich lifts the overlying strata. Dr- ize pie (Di)a:pltr \9 OVER THE OHIO PASS -AT GUNNISON AGA . FISHY YARNS-THE RIVER PORTALS-POETRY AN > GEOLOGY. ^\ 15 lue likes rata. HAVING F'-^-.jta the next morning, September 16, we crossed the Ohio pass, on our re- turn to Gunnison, by a road dif- ferent to that of our previous journey, which had now taken us around a group of three mountnin peaks. Mt. Wheat- stone, Mt. Axtell, and Mt. Carbon, and from the watershed of the Slate river to that of Ohio creek, both tributaries of the Gunnison, into which they merge a little to the north of the town itself. Ohio pass, 10,033 feet above sea- level, is similar to other mountain crossings; there is a defunct sawmill with an untidy heap of saw- dust; an abandoned railroad grade, as though en- gineering skill had failed of breath; a scattering of pines, the straggling procession representing the sur- vivors of those serried ranks that came up the moun- tain-side in proud array until they encountered an invisible bar to further advance — the 'timber line' which, like the shore of an ancient sea, belt? all the mountains and marks the upward limit of the condi- tions favorable to forest growth. i i I 120 ACROSS THE SaN JUAN MOUNTAINS We passed Carbon and Castleton, two coal camps, with all the hideousness that belongs to such settlements ; then a short stay, pleasant for man and horse alike, at a roadside ranch, prepared us for a long canter over the wide dusty road, which finally, but we could never tell when, brought us into the un- limited city of Gunnison. That night at Gunnison we heard the fishermen's tales. It is a great resort for the manipulators of rod and line. It is also a mining centre for the sur- rounding hill-country, so that there is no lack of fishy yarns. The unwary will hear of mountains of iron and acres of gold ore; but behind the exaggera- tion there is the fact that the Gunnison country, with the Elk mountains to the north and the granite foot- hills that lead to the San Juan ranges, to the south, is extremely rich in a variety of mineral wealth — coal, iron, gold, and silver — which would have under- gone more substantial exploitation if the windy breath of a premature boom had not blighted it in the infancy of its development. On September 17 we rode from Gunnison to Gate View. The road follows the Gunnison until it crosses the river at lola, the shipping point of the Vulcan district. Takin;,- a cross-country trail, we filed through the sage-brush covering monotonous low hills, the remnants of granite mountains that had yielded to the leveling hand of Time. ^encer and Dubois, two mining camps, were founc- ."'Imost desiited. Then, surmounting a ridge, we saw again 151 •f GATE VIEW lai the splendor of the San Juan ranges and the pleasant valley of the Lake Fork. After weary miles of sage- brush hillocks it was singularly refreshing to look upon a landscape through the diversified beauty of which the modifying influence of geological structure could be plainly discerned. At Gate View we passed a night. The name is given to a ranch and railroad section-house near the natural gateway of the Lake Fork, which flows through a gap cut in the andesite. A tongue of this eruptive crosses the broad valley; the river has cut its way through; high, nearly ver- tical, cliffs arise on either side; then steep debris slopes, making a broad V, at the bottom of which the road, the railroad, and the river jostle each other for passage ; this framed a view of hills rich in the gold and russet of the aspens, surmounted by the high peaks of the San Juan mountains. Looking through the portals of the river, one is reminded of Ruskin's question concerning a similar natural structure : "When did the great spirit of the river first knock at those adamantine gates? When did the porter open to it and cast his keys away for- ever, lapped in whirling sand?" It is a fine simili- tude; but geology, with less poetic diction, says that the rock is not adamant to the instrument of erosion as used by the running stream with patient persistence through long time, and that no porter was needed to open the gate; the river found a way by obeying the laws of its being — gravity, which impelled it to seek the lowest channel and to deepen that channel i ' ill M 122 ACROSS THE SAN JUAN MOUNTAINS continually, for fear the onlooking hills should fill it up too fast with their discarded debris. The road, farther on, alternately crosses flat stretches of partially cultivated land and descends into the bed of the stream amid narrow gorges cut into andesite-breccia and tuflfs, until at the confluence of Henson creek we rode, under a sharp downpour of cold rain, into the town of Lake City. Gothic Mountain. A Trachytic Mass Overlying Cretaceous Rocks. After James D. Dana. Vli ' nl ClHMpt&r 20 LAKE QTY — THE UTE & ULAY MINES — CONCEN- TRATING MILL — ELECTRICAL DRILLS — ROUGH HANDLING — NEW MILLS. E reached Lake City at noon amid a rainstorm which was re- markable for the reason that it was the first bit of bad weather encountered during twelve days, ft cleared in the afternoon, so, leaving our horses to rest, we walked the seven miles up Hen- son creek to the Ute & Ulay mines. These have been the mainstay of Lake City through all the vicissitudes of the past twenty years. The two veins have been worked at various times both jointly and separately. When I was last there the Ulay lode was the chief source of production; on the present occasion we found that the Ute vein was affording the principal stoping ground. This was above the main adit. The vein is from four to five feet v/ide ; it is a simple quartz vein conaining argentiferous galena. Iron pyrite and zinc-blende are present in relatively small quantity. The lode is essentially an impregnation following a sheeted band in the andesitic breccia of the San Juan formation and has the characteristics already noted at the Camp Bird, Smuggler Union, 124 AC KKSS THE SAN JUAN MOUNTAINS 4l ipjlf-!i \ ' k ! ! Is ^ri ' f' ,1 11 4 and other mines in the same region. Stopes extend, nearly continuously, for half a mile. The Ute dips westward ;i ' 63" and is worked in the adjacent Cali- fornia mine. The Ulay has been worked 700 feet below Henson creek through old workings, which were in had repair; a new vertical shaft had just been started to open up the lower ground on this lode. The mill reminded me, in its method of treat- ment, of the old Foxdale mine, in the Isle of Man, where, however, raff-wheels are used instead of ele- vators and the plant is spread over a much larger area. The treatment is simple and well adapted to the character ( the ore. The mill has a capacity of 90 to 100 tons per day. The ore goes first to a rock-breaker (Blake, 9 by 15 in.) and then to three sets of rol'-i (Allis-Chalmers, 16 by 30 in.), then through four successive trommels, 36 in. diam. and 7 ft. long, which sizr the crushed ore to 8, 6, 4, and 2y2 millimetres. The coarse, which passes through the trommels, goes to the jigs, a double-compartment jig for each trommel. The fine, which escapes from the last trommel, passes into two hydraulic sizers, the coarse being sent to jigs, while the fine goes into a third sizer. The coarse from this last sizer goes to a jig and the fine runs to the buddies. There are two plain buddies, 16 ft. diam., and four double-deck bud- dies, 24 ft. diam., the tailing from which passes into settling-vats, where the slime is arrested. The concentrate is dried and mixed by passing through a heated revolving cylinder. About 1^ per L«r1 H ALONG HENSON CREEK 135 cent of moisture is left in the comentrate, in ordrr to lessen the leakage arising from the bad fooring of the railroad cars, which wtiuld be a greater source of loss if ;1ic concentrate were dry enough to run readily, i .i,- concentrate com tins 58 to 61% lead. 13 to 15 oz. silver and 0.05 to 0.06 oz. gold per ton; this represent* about 16% in weight of the original ore and an extraction of about 80% of the lead and 65vi of the silver. Next day, September 18, saw u.s started on our final stage, from Lake City to Ouray. The road took us again past the Ute & Ulay, where we stopped to get some further data from the millman. As we rode up Hen.son creek it was pleasant to notice a good deal of mining activity ; we passed under the Bleichert tramway of the H«r»den Treasure, past the More mill, with a Leschen ; . n r nnecting it to an unseen mine on the pine-clad noi. t.iT --.-ide, and then, just below Rose's Cabin, the ... uh-m t mnel, with a new mi'' :, course of construe .-, M-. Philip Newitt. suyir'-^- tendent of the Henson C ;eek Lead Mines C ni'.;.;,y as it is officially styled, was kind enough to ;-. us underground. The lode is the usual sheeted band of andesite-breccia, carrying four to five feet of quartz, in which gold, silver, copper, and lead are carried by copper pyrite, galena, and other less conspicuous minerals. This mine afforded an example of the use of electric drills; the Gardner and Durkee were both in use and the superintendent expressed himself as dis- i tl 126 ACROSS THE SAN JUAN MOUNTAINS kt ,N, appointed with them; in each case the motor is carried on a truck and power is transmitted through a flexible shaft. The practical efficiency of the electric drills is a subject too large for passing comment, though it is fair to the inventors to say that the machines suffer from their unpopularity among miners and the fre- quent lack of technical skill on the part of the operator. As a rule the first drill tested in a mine is handled by an expert provided by the company that sells the drill; then, results being deemed good by a manager or director, others are ordered. The drill company's man and his skilled assistants depart, leaving a delicate piece of electrical machinery to the tender mercies of a muscular workman, who starts with a prejudice against anything new and unfamiliar, and is apt to be confirmed in his prejudice by his own inexpert handling of the machine. ' This, of course, is, in a way, the drawback to all electrical machinery — it requires workmen who know something about it — but it is an obstacle that the increasing applica- tion of electricity will overcome, surely. In the meantime I unite with others in the hope that the electric drill will be further improved, because it can facilitate and cheapen mountain mining to an extra- ordinary degree. chapter 21 ROSE'S CABIN — CLIMBING THE RANGE — A SNOW- STORM—BEAR CREEK — AFTER THE STORM — A GLORIOUS PICTURE — ARRIVAL AT OURAY — THE END. \ OSE'S CABIN, at 10,850 feet, just above the Bonanza mine- bu Mings, is a landmark. It was a stopping place in the old days of transmontaine travel when long lines of pack-mules and horsemen were wont to file up Henson creek on their way to Silverton, Rico, and Ouray. We took the right-hand trail, past the Palmetto mill and along the old grade to the Frank Hough mine. As we climbed the range, the snow-mists gath- ered, and when we finally reached the crest, at 12,850 feet, the mountains were robed in all th; magnificence of the storm. The cold blast from the canon below swept up to the summit of the range, driving a chilly mist, which flung itself fiercely around every crag and threw great shadows that stalked swiftly across the darkening slopes. Here and there amid the gloom a lonely peak c.-ught the light, a Titan head above the sea of cloud. Thus we saw old Uncompahgre and the Wetterhorn, besides many another unnamed »1 128 ACROSS THE SAN JUAN MOUNTAINS m * 11 it crest. While we waited, the hail and snow came fast, and so, without further delay, we began the slow descent of the other side, leading and pulling our shivering horses down the tedious talus slopes. Soon we reached the warmer air of Bear creek basin, a spacious amphitheatre near the timber-line, from which a well-marked trail took us into Bear creek caiion, a narrow gorge, lined by the most astounding precipices and picturesque to a degree that was astonishing even after two weeks of moun- tain scenery. The andesite-breccia, in nearly level layers, forms cliffs that sweep from an eerie height of a thousand feet, and more, down into the hidden bed of a torrent. The sheeted structure, due to parallel- ism of nearly vertical fractures, is noticeable, and the sympathetic structure of the veins is apparent even at a distance, for their outcrops are clearly visible, ribbing the rock faces with broken lines cf quartz. We passed the Yellow Jacket and the Grizzly Bear mines, huddled under the beetling brows of breccia cliffs, where, here and there, a cluster of courageous pines clung hungrily for life, or a solitary cabin looked calmly over the abyss, or faint trails in unexpected tracery of line wound in and out of dark ravines with the veritable unconscious air of gentle- men without visible means of support. Our progress, over a trail which was a narrow, albeit quite safe, ledge between rock and torrent, was necessarily, with horses, a slow business. At length, after hours of a continuous descent, which seemed z II ^^^^H fI til 11 'HI ^ if ^1 jkj£k.«: STORM ON THE RANGE 129 interminable and gave us a singular feeling of going right into the depths of the earth, we emerged sud- denly into full view of the Uncompahgre valley. It is no exaggeration to say that all four of us, some of w^hom had made the voyage rotmd th«» world more than once, were amazed at the grandeur of the great picture before us. Scattered already to the four winds, as becomes mining engineetfs,'* we shall, I believe, always remember titat "polychrome of splen- dor, an exultation to recall. ' Ruskin would have rhapsodized over it and Clarence Kmg could have described it.'* The storm had swept northward, the sky was still partly overcast with flying ek)ud, a luminous atmosphere, pure as interplanetary space, filled the cafion depths, and from the west the sonlight pierced the lingering mists with mellow light. We stood on a narrow promontory. Across the caiion the ter- raced slopes descended in parklike gradation, re- splendent with the livery of autumn, and above their aspen gold \he bsistions of hiue-gray andesite rose tier after tier in Gothic severity cff line until belted with the rising mists. Up the valley to the left the winding thread of the river led to the nyramid of Mt. Abram, his sentniel he.ad aglow with sunlight, while farther south rose the Red mountams, shrouded "One is in Western Australia, another in California. tJw Awii :■; in Mexico, and the fourth in N'ew York City. This gives me the iip|>ortiinity of recommending to -fw friends that most delightful book ot Clarence King, 'Mountaineering m the Sierra Nevada.' t'l'- 130 ACROSS THE SAN JUAN MOUNTAINS in cold vapor that dimmed their volcanic tii Straight in front and northward, overtopping th swiftly changing visions of rich coloring and sci tured line, there gleamed the Mt. SneflFels rant freshly ennobled by a coronet of snow, with a gr passion of light glowing about their lordly summ while in the darkening east there trailed away gray-winged form, the ghost of wind and rain." It will seem something of an anti-climax state that the trail subsequently led us to an intere mg geological section, where the breccia of t Eocene period was found resting upon the upturn edges of pre-Cambrian slates and quartzite, with or a thin layer of conglomerate, possibly a represem tive of the Telluride formation, between them \ reached Ouray before dark, having completed a ri of fully 400 miles. "For what high end is all this daily boon, Unseen of man, in sightless silence spent? Doth lavish Nature vainly importune The unconscious witness of the firmament? "Or. is it that the influent God, whose breath Informs witn glory sea, and shore, and hill, His mfmite lone rejoicing nourisheth Upon the bounteous outcome of His will? — Brunton Sincns. JNS :anic tints, pping these and sculp- 'els ranges, ^ith a great y summits, d away "a rain." -climax to iri interest- cia of the e upturned , with only •epresenta- hem. We sted a ride J f^^ m